#include <iostream>
#include <stack>
#include <string>

using namespace std;

bool first(char c){
    if(c == '(' || c == '{' || c == '[') return true;
    return false;
}

bool last(char c){
    if(c == ')' || c == ']' || c == '}') return true;
    return false;
}

bool match(char a, char b){
    if(a == '(' && b == ')') return true;
    if(a == '{' && b == '}') return true;
    if(a == '[' && b == ']') return true;
    return false;
}

bool isValid(const string& s){
    if(s.empty()) return true;
    if(last(s[0])) return false;
    if(s.length() % 2 == 1) return false;
    
    int len = s.length();
    stack<char> st;
    
    for(int i = 0; i < len; ++i){
        if(first(s[i])) st.push(s[i]);
        if(last(s[i])){
            char top = st.top();
            if(match(top, s[i])) st.pop();
            else return false;
        }
    }
    if(!st.empty()) return false;
    return true;
}

int main(){
    string s;
    getline(cin, s);
    cout << (isValid(s) ? "true" : "false") << endl;
    return 0;
}