diff --git a/exercises/13_error_handling/errors3.rs b/exercises/13_error_handling/errors3.rs
index 33a7b877..8e8c38a2 100644
--- a/exercises/13_error_handling/errors3.rs
+++ b/exercises/13_error_handling/errors3.rs
@@ -19,6 +19,7 @@ fn main() {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
+    // Don't change this line.
     let cost = total_cost(pretend_user_input)?;
 
     if cost > tokens {