import java.util.*;
class Solution {
    
    public static void main(String[] argh) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            String input = sc.next();
            // Create stack to track opening brackets
            Stack<Character> stack = new Stack<>();
            // Loop through the characters of the string
            boolean isValid = true; // Track if the string is valid
            for (int i = 0; i < input.length(); i++) {
                Character ch = input.charAt(i);
                
                // If it's an opening bracket, push to the stack
                if (ch == '{' || ch == '(' || ch == '[') {
                    stack.push(ch);
                } 
                // If it's a closing bracket
                else if (ch == '}' || ch == ')' || ch == ']') {
                    // If stack is empty, it's an unmatched closing bracket
                    if (stack.isEmpty()) {
                        isValid = false;
                        break; // Exit the loop early
                    }
                    // Pop from stack and check if the brackets match
                    char top = stack.pop();
                    if ((ch == '}' && top != '{') || 
                        (ch == ')' && top != '(') || 
                        (ch == ']' && top != '[')) {
                        isValid = false;
                        break; // Exit the loop early
                    }
                }
            }
            
            // After processing all characters, the stack must be empty
            if (isValid && stack.isEmpty()) {
                System.out.println("true");
            } else {
                System.out.println("false");
            }
        }
    }
}