70分，AC7个点，WA3个点

代码如下：

#include <bits/stdc++.h>
using namespace std;
char ssbb[270];
string ikun114514;
int i,cnt,cnt2;
int main(){
    while(1){
        cin >> ssbb[i];
        if(ssbb[i]=='@') break;
        else if(ssbb[i]=='(') cnt++;
        else if(ssbb[i] == ')') cnt2++;
        i++;
    }
    ikun114514 = ssbb;
    if(cnt == cnt2) cout << "YES";
    else cout << "NO";
}