diff --git a/solutions/13_error_handling/errors4.rs b/solutions/13_error_handling/errors4.rs
index 7f176cf..70c5f1c 100644
--- a/solutions/13_error_handling/errors4.rs
+++ b/solutions/13_error_handling/errors4.rs
@@ -1,3 +1,5 @@
+use std::cmp::Ordering;
+
 #[derive(PartialEq, Debug)]
 enum CreationError {
     Negative,