Runtime Error
foo.cc:45:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
45 | main(){ ios::sync_with_stdio(0); cin.tie(0);
| ^~~~
正在同步测试数据，请稍后 [Hydro](https://hydro.ac)提供评测服务
foo.cc:45:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
45 | main(){ ios::sync_with_stdio(0); cin.tie(0);
| ^~~~
正在同步测试数据，请稍后 [Hydro](https://hydro.ac)提供评测服务
