1 задача

// () yes
// (( no
#include <iostream>
#include <stack>

using namespace std;

int  main() {
    char clip;
    stack<char> bracket;

    while (cin >> clip) {
        switch (clip) {
            case '(': {
                bracket.push(clip);
                break;
            }
            case ')': {
                if (!(bracket.empty())) {
                    if ('(' == bracket.top()) {
                        bracket.pop();
                    } else {
                        cout << "no";
                        return 0;
                    }
                }
                else {
                    cout << "no";
                    return 0;
                }
                break;
            }
        }

    }

    if (bracket.empty()) {
        cout << "yes";
    }
    else
    {
        cout << "no";
    }
}