diff --git a/du6/program.c b/du6/program.c
index e11f303..e7e852c 100644
--- a/du6/program.c
+++ b/du6/program.c
@@ -89,7 +89,7 @@ intmax_t readMaxCount(char *buffer, int size) {
     char *endPtr;
     intmax_t result = strtoimax(buffer, &endPtr, 10);
 
-    if (errno == ERANGE || endPtr != buffer + (l - 1)) {
+    if (errno == ERANGE || result == 0 || endPtr != buffer + (l - 1)) {
         return -1;
     }