diff --git a/src/days/d18.rs b/src/days/d18.rs
index 7219b57..918c856 100644
--- a/src/days/d18.rs
+++ b/src/days/d18.rs
@@ -3,7 +3,7 @@ use crate::prelude::*;
 pub type I = &'static str;
 pub type O = usize;
 
-// @TODO: try bit mast approach
+// @TODO: try bit mask approach
 fn _solve (data: I, rows: usize) -> O {
     let w = data.len();
     let mut v = vec![data.to_owned()];