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.ArrayDeque;
import java.util.Deque;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		new Main().run();
	}

	void run() {
		Scanner sc = new Scanner(System.in);
		String line = sc.nextLine();
		String[] lineArr = line.split(" ");

		Deque<String> stack = new ArrayDeque<String>();
		for (String s : lineArr) {
			if ("+".equals(s)) {
				int a = Integer.parseInt(stack.pop());
				int b = Integer.parseInt(stack.pop());
				stack.push(String.valueOf(a + b));
			} else if ("-".equals(s)) {
				int a = Integer.parseInt(stack.pop());
				int b = Integer.parseInt(stack.pop());
				stack.push(String.valueOf(b - a));
			} else if ("*".equals(s)) {
				int a = Integer.parseInt(stack.pop());
				int b = Integer.parseInt(stack.pop());
				stack.push(String.valueOf(a * b));
			} else {
				stack.push(s);
			}
		}
		System.out.println(stack.pop());
	}
}