diff --git a/src/tasks/day05.rs b/src/tasks/day05.rs
index 0e80d04..72577db 100644
--- a/src/tasks/day05.rs
+++ b/src/tasks/day05.rs
@@ -22,7 +22,7 @@ pub fn task2() {
                 reduce(
                     &input
                         .chars()
-                        .filter(|ch| ch.to_lowercase().next().unwrap() != c)
+                        .filter(|ch| ch.eq_ignore_ascii_case(&c))
                         .collect::<String>(),
                 ).len(),
             )