import java.util.*; class Solution{

public static void main(String []argh)
{
    Scanner sc = new Scanner(System.in);

    while (sc.hasNext()) {
        String input=sc.next();
        //Complete the code

        Stack <Character> s = new Stack<>();
        for(int i = 0 ; i<input.length(); i++)
        {
            char  c = input.charAt(i);

            if(c=='{' || c=='(' ||  c=='[')
            {
                s.push(c);
            }
           else if(s.size()!=0 && ((c=='}' && s.peek()=='{') || (c==')' && s.peek()=='(') || (c==']' && s.peek()=='[')))
           {
            s.pop();
           }
           else{
            s.push(c);
           }

        }
        if(s.size()==0) System.out.println("true");
        else System.out.println("false");
    }

}

}