import java.util.*;

public class OurStackExample {

    public static void main (String[] argv)
    {
	String s = "((()))";
	checkParens (s);

	s = "()(())()";
	checkParens (s);

	s = "((())";
	checkParens (s);
    }

    static void checkParens (String inputStr)
    {
	char[] letters = inputStr.toCharArray();
	OurStack stack = new OurStack ();

	boolean unbalanced = false;
	for (int i=0; i<letters.length; i++) {
	    if (letters[i] == '(') {
		stack.push (letters[i]);
	    }
	    else if (letters[i] == ')') {
		// We should have a match on the stack.
		// We need this in case it's empty up front.
		char ch = ')';
		if (! stack.isEmpty() ) {
		    ch = stack.pop ();
		}
		if (ch != '(') {
		    // Oops.
		    unbalanced = true;
		    break;
		}
	    }
	}
	
	if ( (unbalanced) || (! stack.isEmpty()) ) {
	    System.out.println ("String " + inputStr + " has unbalanced parens");
	}
	else {
	    System.out.println ("String " + inputStr + " has balanced parens");	
        }
    }

}