diff --git a/du3/program.c b/du3/program.c
index b21146a..dc96e33 100644
--- a/du3/program.c
+++ b/du3/program.c
@@ -80,8 +80,8 @@ if (sscanf(buffer, " %f %c", &chyslo, &symbol) == 1) {  //спроба проч
             }
             print_stack(&mystack);
         } else {
-            printf("invalid input\n");
-            return 1;
+            printf("bad input\n");
+            return 0;
         }
     }
     printf("no input\n");