H1

#include <iostream>
using namespace std;

int main() {
    string s;
    cin >> s;
    bool flag = true;
    string s1;
    for(const auto& x : s){
        if(x == '(' || x == '[' || x == '{'){
            s1.push_back(x);
        } else{
            if(s1.empty()){
                flag = false;
                break;
            }
            if(x - s1.back() == 1 || x - s1.back() == 2){
                s1.pop_back();
            } else{
                flag = false;
                break;
            }
        }
    }
    if(!s1.empty()){
        flag = false;
    }
    if(flag){
        cout << "yes\n";
    } else{
        cout << "no\n";
    }
    return 0;
}