diff --git a/du4/program.c b/du4/program.c
index 22ad1c1..6c50d5f 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
-#include <sting.h>
+#include <string.h>
 #include <stdbool.h>
 
 int main(){