import java.util.Stack;

public class SymbolsChecker {
	public static void main(String[] args) {
		test("(())");
		test("()");
		test("())");
		test("((");
	}
	
	public static void test(String s) {
		System.out.print(s + " is ");
		if (!symbolsBalanced(s)) {
			System.out.print("NOT ");
		}
		System.out.println("balanced");
	}
	
	public static boolean symbolsBalanced(String s) {
		Stack<Character> symbols = new Stack<Character>();
		
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == '(' || c == '{') {
				symbols.push(c);
			} else if (c == ')' && (symbols.isEmpty() || symbols.pop() != '(')) {
				return false;
			} else if (c == '}' && (symbols.isEmpty() || symbols.pop() != '{')) {
				return false;
			}
		}
		
		return symbols.isEmpty();		
	}
		
}