diff --git a/main.rkt b/main.rkt
index 79a8b3a..5f90736 100644
--- a/main.rkt
+++ b/main.rkt
@@ -1,6 +1,7 @@
 #lang racket
 
 (require racket/gui)
+(require (prefix-in str: srfi/13))
 
 (provide ellipsis-msg%)