import java.util.*;
import java.io.*;
 
public class calculator {
 
	private String infix;
	private String postfix = " ";
 
//	public calculator(String in) {
	//	input = in;
	//	int SIZE = input.length();
 
//	}
 
	public String toPostfix(String infix) {
 
		String expression;
		String postfix = " ";
 
		Stack operatorStack = new Stack();
 
		StringTokenizer s = new StringTokenizer(infix);
 
		while (s.hasMoreTokens()) {
 
			expression = s.nextToken();
			if (Character.isDigit(expression.charAt(0)))
				postfix = postfix + " " + (Integer.parseInt(expression));
			else if (expression.equals("("))
 
			{
				Character operator = new Character('(');
				operatorStack.push(operator);
			} else if (expression.equals(")"))
 
			{
				while (((Character) operatorStack.peek()).charValue() != '(') {
					postfix = postfix + " " + operatorStack.pop();
				}
				operatorStack.pop();
			} else
 
			{
				while (!operatorStack.isEmpty()
						&& !(operatorStack.peek()).equals("(")
						&& prec(expression.charAt(0)) <= prec(((Character) operatorStack
								.peek()).charValue()))
					postfix = postfix + " " + operatorStack.pop();
				Character operator = new Character(expression.charAt(0));
				operatorStack.push(operator);
			}
		}
		while (!operatorStack.isEmpty())
			postfix = postfix + " " + operatorStack.pop();
		return postfix;
	}
 
	private static int prec(char x) {
		if (x == '+' || x == '-')
			return 1;
		if (x == '*' || x == '/' || x == '%')
			return 2;
		return 0;
	}
 
	public  int evaluate(String postfix) {
		int a;
		int b;
		int result = 0;
 
		Stack<Integer> myStack = new Stack<Integer>();
 
		for (int i = 0; i < postfix.length(); i++) {
			char ch = postfix.charAt(i);
			if (ch >= '0' && ch <= '9') {
				myStack.push((int) (ch - '0'));
 
			} else {
				switch (ch) {
				case '+':
					a = myStack.pop();
					b = myStack.pop();
					result = a + b;
					myStack.push(result);
					break;
 
				case '-':
					a = myStack.pop();
					b = myStack.pop();
					result = a - b;
					myStack.push(result);
					break;
 
				case '*':
					a = myStack.pop();
					b = myStack.pop();
					result = a * b;
					myStack.push(result);
					break;
				case '/':
					a = myStack.pop();
					b = myStack.pop();
					result = a / b;
					myStack.push(result);
					break;
 
				}
				myStack.push(result);
 
			}
		}
		myStack.push(result);
		return result;
	}
}

        Stack<Integer> myStack = new Stack<Integer>() {
 
            public Integer push(Integer i) {
                Integer j = super.push(i);
                System.out.println("push " + i);
                return j;
            }
 
            public Integer pop() {
                Integer i = super.pop();
                System.out.println("pop " + i);
                return i;
            }
        };