```cpp
#include<bits/stdc++.h>
using namespace std;
stack<char>stk;
int main() {
char a;
while(cin>>a&&a!='@'){
if(a=='(')
stk.push(a);
if(a==')')
if(stk.empty())
return cout<<"NO",0;
else
stk.pop();
}
if(!stk.empty()) return cout<<"NO",0;
return cout<<"YES",0;
}
```
by brown_me @ 2023-09-11 13:50:45