#include <iostream>
#include <stack>
#include <string>
#include <stdio.h>
#include <set>
#include <cstdio>
using namespace std;

#include <cstdio>
using namespace std;
int main() {
    char ch;
    stack<char> myStack;
    while (scanf("%c", &ch)) {
        if ((ch == '(') || (ch == '[') || (ch == '{')) {
            myStack.push(ch);
        } else if (ch == ')') {
            if ((myStack.size() == 0) || (myStack.top() != '(')) {
                cout << "no" << endl;
                return 0;
            } else {
                myStack.pop();
            }
        } else if (ch == ']') {
            if ((myStack.size() == 0) || (myStack.top() != '[')) {
                cout << "no" << endl;
                return 0;
            } else {
                myStack.pop();
            }
        } else if (ch == '}') {
            if ((myStack.size() == 0) || (myStack.top() != '{')) {
                cout << "no" << endl;
                return 0;
            } else {
                myStack.pop();
            }
        }
    }

    if (myStack.size() == 0) {
        cout << "yes" << endl;
    } else {}
        cout << "no" << endl;
}