#include <bits/stdc++.h>

using namespace std;
stack<char> _a;

int main() {
    ios::sync_with_stdio(false); //读入输出优化的强迫症
    string str = "";
    cin >> str;
    for (int i = 0; i < str.size(); i++) {
        if (str[i] == '@') break;
        if (str[i] == '(') _a.push(str[i]);
        if (str[i] == ')') {
            if (!_a.empty()) {
                _a.pop();
            } else {
                cout << "NO" << endl;
                return 0;
            }
        }
    }
    if (_a.empty()) cout << "YES" << endl;//判断有没有多余的(
    else cout << "NO" << endl;//也就是判断栈是否为空
    return 0;
}