#include using namespace std; int main() { char c; int score = 0; while(true) { cin >> c; if(cin.eof()) { break; } if(c == '(') { score++; } else if(c == ')') { if(--score < 0) { cout << "no" << endl; return 0; } } } if(score) { cout << "no" << endl; return 0; } cout << "yes" << endl; return 0; }