90.

2023209/main.cpp

@@ -61,6 +61,10 @@ int main() {
     scanf("%hu %hu %d", &start, &terminal, &time_limit);
 
     dfs(start, 0, 0, 0);
+    if (current_cheap == 2147483647) {
+        printf("-1\n");
+        return 0;
+    }
     printf("%d\n", current_cheap);
     return 0;
 }