#include <iostream>
#include <unordered_map>
#include <vector>

bool CheckSequence(const std::string &brackets) {
    std::vector<char> stack;
    std::unordered_map<char, char> brackets_dict{{'}', '{'}, {']', '['}, {')', '('}};
    for (auto bracket : brackets) {
        if (brackets_dict.count(bracket) == 0) {
            stack.push_back(bracket);
        } else if (!stack.empty() && brackets_dict[bracket] == stack.back()) {
            stack.pop_back();
        } else {
            return false;
        }
    }
    return stack.empty();
}


int main() {
    std::vector<char> stack;
    std::string brackets;
    std::cin >> brackets;
    if (CheckSequence(brackets)) {
        std::cout << "yes";
    } else {
        std::cout << "no";
    }
}