文件目录

#include <bits/stdc++.h>
using namespace std;
string s;
bool pd(string s)
{
    int n = 0;
    for (int i = 0; s[i] != '@'; i++)
    {
        if (s[i] == '(')
            n++;
        else if (s[i] == ')')
        {
            if (n == 0)
                return false;
            else
                n--;
        }
    }
    if (n == 0)
        return true;
    else
        return false;
}
int main()
{
    cin >> s;
    if (pd(s))
        cout << "YES";
    else
        cout << "NO";
    return 0;
}