diff --git a/du3/program.c b/du3/program.c
index 59f088b..c05866a 100644
--- a/du3/program.c
+++ b/du3/program.c
@@ -89,7 +89,7 @@ int main()
         char input[1000];
         while (fgets(input,sizeof(input),stdin)!=NULL)
         {
-		if((input[0]>=0 && input[0]<=47) || (input[0]>=58 && input[0]<=127))
+		if((input[0]>0 && input[0]<=47) || (input[0]>=58 && input[0]<=127))
 		{
 			printf("bad input\n");
 			return 0;