bool balanced(string s)
{

     stack <char> letters;
     int open = 0;
     int close = 0;
     
     for (int i=0; i<s.length(); i++) {
          letters.push(s.at(i));
     }
     
     while (!letters.empty()) {
           if (isOpen(letters.top())) {
                open++;
           }
           else if (isClose(letters.top())) {
                close++;
           }
           
           letters.pop();
     }
     
     if (open == close) {
         return true;
     }
     else return false;

}