diff --git a/Cargo.lock b/Cargo.lock
index 25c2b24..379ec3a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -17,11 +17,21 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "aoc2024"
 version = "0.1.0"
 dependencies = [
  "color-eyre",
+ "regex",
  "tracing",
  "tracing-subscriber",
 ]
@@ -199,6 +209,35 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "regex"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.24"
diff --git a/Cargo.toml b/Cargo.toml
index 4f81e20..4d3ca00 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,5 +8,6 @@ edition = "2021"
 
 [dependencies]
 color-eyre = "0.6.3"
+regex = "1.11.1"
 tracing = "0.1.41"
 tracing-subscriber = "0.3.19"
diff --git a/inputs/day03/example.txt b/inputs/day03/example.txt
new file mode 100644
index 0000000..f274bda
--- /dev/null
+++ b/inputs/day03/example.txt
@@ -0,0 +1 @@
+xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))
diff --git a/inputs/day03/example_2.txt b/inputs/day03/example_2.txt
new file mode 100644
index 0000000..b774ec9
--- /dev/null
+++ b/inputs/day03/example_2.txt
@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))
\ No newline at end of file
diff --git a/src/day01.rs b/src/day01.rs
index 0e8e0c5..ff2dfbf 100644
--- a/src/day01.rs
+++ b/src/day01.rs
@@ -33,7 +33,7 @@ pub fn pt2(input: &str) -> usize {
 mod tests {
     use std::fs::read_to_string;
 
-    use crate::day01::{pt1, pt2};
+    use super::{pt1, pt2};
 
     #[test]
     pub fn test_pt1() {
diff --git a/src/day02.rs b/src/day02.rs
index fbf0b92..defc189 100644
--- a/src/day02.rs
+++ b/src/day02.rs
@@ -46,7 +46,7 @@ pub fn pt2(input: &str) -> usize {
 mod tests {
     use std::fs::read_to_string;
 
-    use crate::day02::{pt1, pt2};
+    use super::{pt1, pt2};
 
     #[test]
     pub fn test_pt1() {
diff --git a/src/day03.rs b/src/day03.rs
new file mode 100644
index 0000000..8a24af5
--- /dev/null
+++ b/src/day03.rs
@@ -0,0 +1,42 @@
+use regex::Regex;
+
+pub fn pt1(input: &str) -> usize {
+    let re = Regex::new(r"mul\((\d+),(\d+)\)").unwrap();
+    re.captures_iter(input)
+        .map(|c| c.extract())
+        .map(|(_, [x, y])| x.parse::<usize>().unwrap() * y.parse::<usize>().unwrap())
+        .sum()
+}
+
+pub fn pt2(input: &str) -> usize {
+    let re = Regex::new(r"mul\((\d+),(\d+)\)").unwrap();
+    re.captures_iter(
+        &Regex::new(r"don't\(\).*?do\(\)")
+            .unwrap()
+            .replace_all(&input.replace('\n', ""), ""),
+    )
+    .map(|c| c.extract())
+    .map(|(_, [x, y])| x.parse::<usize>().unwrap() * y.parse::<usize>().unwrap())
+    .sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use std::fs::read_to_string;
+
+    use super::{pt1, pt2};
+
+    #[test]
+    pub fn test_pt1() {
+        let input =
+            read_to_string("./inputs/day03/example.txt").expect("Missing example.txt for day03");
+        assert_eq!(pt1(&input), 161)
+    }
+    #[test]
+    pub fn test_pt2() {
+        let input = read_to_string("./inputs/day03/example_2.txt")
+            .expect("Missing example_2.txt for day03");
+
+        assert_eq!(pt2(&input), 48)
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 4d054bd..d00b4de 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,11 +2,13 @@ use std::{fmt::Display, fs::read_to_string, time::Instant};
 
 mod day01;
 mod day02;
+mod day03;
 fn main() {
     color_eyre::install().unwrap();
     tracing_subscriber::fmt::init();
-    solve_day(01, day01::pt1, day01::pt2);
-    solve_day(02, day02::pt1, day02::pt2);
+    solve_day(1, day01::pt1, day01::pt2);
+    solve_day(2, day02::pt1, day02::pt2);
+    solve_day(3, day03::pt1, day03::pt2); 
 }
 
 fn solve_day<Fa, Fb, Ta, Tb>(day: u8, part_a: Fa, part_b: Fb)
@@ -16,8 +18,8 @@ where
     Fb: Fn(&str) -> Tb,
     Tb: Display,
 {
-    let input = read_to_string(format!("./inputs/day{:02}/input.txt", day))
-        .expect(&format!("Missing input.txt for day{:02}", day));
+    let input = read_to_string(format!("./inputs/day{day:02}/input.txt"))
+        .unwrap_or_else(|_| panic!("Missing input.txt for day{day:02}"));
     let start = Instant::now();
     let result_a = part_a(&input);
     tracing::info!("[{day:02}] Part A: {result_a} \tin {:?}", start.elapsed());