Notes

Template in C

Constraints

2 ≤ the number of operands in the expression ≤ 100
1 ≤ the number of operators in the expression ≤ 99
-1 × 109 ≤ values in the stack ≤ 109

Input

An expression is given in a line. Two consequtive symbols (operand or operator) are separated by a space character.

You can assume that +, - and * are given as the operator and an operand is a positive integer less than 106

Output

Print the computational result in a line.

Examples

Input

1 2 +


Output

3


Input

1 2 + 3 4 - *


Output

-3

import java.util.Stack;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		
		Scanner in = new Scanner(System.in);
		Stack<String> expr = new Stack<>();
		while (in.hasNext()) {
			String next = in.next();
			if (next.equals("+")) {
				int a = Integer.parseInt(expr.pop());
				int b = Integer.parseInt(expr.pop());
				int result = a + b;
				expr.push((result + ""));
			} else if(next.equals("-")) {
				int a = Integer.parseInt(expr.pop());
				int b = Integer.parseInt(expr.pop());
				int result = b - a;
				expr.push((result + ""));
			} else if (next.equals("*")) {
				int a = Integer.parseInt(expr.pop());
				int b = Integer.parseInt(expr.pop());
				int result = a * b;
				expr.push((result + ""));
			} else {
				expr.push(next);
			}
			
		}
		System.out.println(expr.peek());
	}
}

