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.Scanner;

import static java.lang.Integer.parseInt;

import java.util.*;

public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        String symbol;
        ArrayDeque<Integer> stack = new ArrayDeque<Integer>();

        while (sc.hasNext()) {
            symbol = sc.next();

            if (symbol.equals("+")) {
                stack.push(stack.pop() + stack.pop());
            } else if (symbol.equals("-")) {
                stack.push((stack.pop() * -1) + stack.pop());
            } else if (symbol.equals("*")) {
                stack.push(stack.pop() * stack.pop());
            } else {
                stack.push(Integer.parseInt(symbol));
            }
        }
        System.out.println(stack.pop());
    }
}
