07. Balanced Parenthesis

#include <iostream>
#include <stack>

using namespace std;

int main() {
    string str;
    cin >> str;

    stack<char> openBrackets;

    for (char c : str) {
        if (c == '(' || c == '[' || c == '{') {
            openBrackets.push(c);
        }
        else if (openBrackets.size() == 0 ||
            c == ')' && openBrackets.top() != '(' ||
            c == ']' && openBrackets.top() != '[' ||
            c == '}' && openBrackets.top() != '{') {
            cout << "NO\n";
            return 0;
        }
        else {
            openBrackets.pop();
        }
    }

    cout << "YES\n";
    return 0;
}