diff --git a/src/main.rs b/src/main.rs
index 26a7f4c..f36f908 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,5 @@
+// https://adventofcode.com/2022/day/5
+
 use regex::Regex;
 
 const DATA: &'static str = include_str!("input.txt");