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

    while (sc.hasNext()) {
        String input=sc.next();
        String[] values = input.split("");
        Stack<String> stack = new Stack<>();
        Map<String, String> chars = new HashMap<>();
        chars.put("(", ")");
        chars.put("{", "}");
        chars.put("[", "]");
        boolean malformed = false;

        for (String value: values){
            if (chars.keySet().contains(value)){
                stack.add(value);
            } else {
                try{
                    String openingChar = stack.pop();
                    if (!chars.get(openingChar).equals(value)){
                        malformed = true;
                    }    
                } catch (EmptyStackException e){
                    malformed = true;
                }

            }
        }
        System.out.println(stack.isEmpty() && !malformed ? "true" : "false");

        //Complete the code
    }

}