diff --git a/2017/rust/Cargo.lock b/2017/rust/Cargo.lock
index 1808e55..d6adbc5 100644
--- a/2017/rust/Cargo.lock
+++ b/2017/rust/Cargo.lock
@@ -4,6 +4,15 @@ version = "0.1.0"
 dependencies = [
  "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "aho-corasick"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "memchr 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -86,11 +95,36 @@ name = "libc"
 version = "0.2.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "memchr"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.34 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "quote"
 version = "0.3.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "regex"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aho-corasick 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "thread_local 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "utf8-ranges 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.5"
@@ -123,11 +157,38 @@ dependencies = [
  "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "thread_local"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unreachable 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "unicode-xid"
 version = "0.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "unreachable"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "utf8-ranges"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "void"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "winapi"
 version = "0.2.8"
@@ -139,6 +200,7 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [metadata]
+"checksum aho-corasick 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "d6531d44de723825aa81398a6415283229725a00fa30713812ab9323faa82fc4"
 "checksum backtrace 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8709cc7ec06f6f0ae6c2c7e12f6ed41540781f72b488d83734978295ceae182e"
 "checksum backtrace-sys 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "44585761d6161b0f57afc49482ab6bd067e4edef48c12a152c237eb0203f7661"
 "checksum cc 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a9b13a57efd6b30ecd6598ebdb302cca617930b5470647570468a65d12ef9719"
@@ -149,11 +211,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c8f31047daa365f19be14b47c29df4f7c3b581832407daabe6ae77397619237d"
 "checksum libc 0.2.34 (registry+https://github.com/rust-lang/crates.io-index)" = "36fbc8a8929c632868295d0178dd8f63fc423fd7537ad0738372bd010b3ac9b0"
+"checksum memchr 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "796fba70e76612589ed2ce7f45282f5af869e0fdd7cc6199fa1aa1f1d591ba9d"
 "checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
+"checksum regex 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ac6ab4e9218ade5b423358bbd2567d1617418403c7a512603630181813316322"
+"checksum regex-syntax 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ad890a5eef7953f55427c50575c680c42841653abd2b028b68cd223d157f62db"
 "checksum rustc-demangle 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "aee45432acc62f7b9a108cc054142dac51f979e69e71ddce7d6fc7adf29e817e"
 "checksum syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d3b891b9015c88c576343b9b3e41c2c11a51c219ef067b264bd9c8aa9b441dad"
 "checksum synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a393066ed9010ebaed60b9eafa373d4b1baac186dd7e008555b0f702b51945b6"
 "checksum synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3a761d12e6d8dcb4dcf952a7a89b475e3a9d69e4a69307e01a470977642914bd"
+"checksum thread_local 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "279ef31c19ededf577bfd12dfae728040a21f635b06a24cd670ff510edd38963"
 "checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"
+"checksum unreachable 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "382810877fe448991dfc7f0dd6e3ae5d58088fd0ea5e35189655f84e6814fa56"
+"checksum utf8-ranges 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "662fab6525a98beff2921d7f61a39e7d59e0b425ebc7d0d9e66d316e55124122"
+"checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
diff --git a/2017/rust/Cargo.toml b/2017/rust/Cargo.toml
index 91a9f32..7fdc2ec 100644
--- a/2017/rust/Cargo.toml
+++ b/2017/rust/Cargo.toml
@@ -6,3 +6,4 @@ authors = ["Alpha Chen <alpha.chen@gmail.com>"]
 [dependencies]
 failure = "0.1"
 lazy_static = "1.0"
+regex = "0.2"
diff --git a/2017/rust/src/day_15.rs b/2017/rust/src/day_15.rs
index acdf66f..c429d43 100644
--- a/2017/rust/src/day_15.rs
+++ b/2017/rust/src/day_15.rs
@@ -1,19 +1,30 @@
 use failure::*;
+use regex::Regex;
+
+pub fn solve(input: &str) -> Result<String, Error> {
+    let re: Regex = Regex::new(r"\d+")?;
+    let matches: Vec<_> = re.find_iter(input)
+        .map(|x| x.as_str())
+        .map(str::parse)
+        .collect::<Result<_, _>>()?;
+    let a_start = matches[0];
+    let b_start = matches[1];
+    // let a_start = 679;
+    // let b_start = 771;
 
-pub fn solve(_: &str) -> Result<String, Error> {
     let a = Generator {
-        value: 679,
-        factor: 16807,
+        value: a_start,
+        factor: 16_807,
     };
     let b = Generator {
-        value: 771,
-        factor: 48271,
+        value: b_start,
+        factor: 48_271,
     };
 
     let answer = a.filter(|a| a % 4 == 0)
         .zip(b.filter(|b| b % 8 == 0))
         .take(5_000_000)
-        .filter(|&(a, b)| a & 0b1111111111111111 == b & 0b1111111111111111)
+        .filter(|&(a, b)| a & 0b1111_1111_1111_1111 == b & 0b1111_1111_1111_1111)
         .count();
     Ok(answer.to_string())
 }
@@ -28,7 +39,7 @@ impl Iterator for Generator {
 
     fn next(&mut self) -> Option<Self::Item> {
         self.value *= self.factor;
-        self.value %= 2147483647;
+        self.value %= 2_147_483_647;
         Some(self.value)
     }
 }
diff --git a/2017/rust/src/main.rs b/2017/rust/src/main.rs
index bc2f8e2..ff8c10f 100644
--- a/2017/rust/src/main.rs
+++ b/2017/rust/src/main.rs
@@ -3,6 +3,7 @@
 extern crate failure;
 #[macro_use]
 extern crate lazy_static;
+extern crate regex;
 
 use std::io::{self, Read};