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.io.*;
import java.util.*;

public class Main {
    public static void main(String args[]) {
        String s;

        Scanner sc = new Scanner(System.in);
        s = sc.nextLine();

        Scanner scn = new Scanner(s);

        Stack<Integer> stack = new Stack<Integer>();

        while (scn.hasNext()) {
            String op = scn.next();
            if (op.equals("+")) {
                int n = stack.pop() + stack.pop();
                stack.push(n);
            } else if (op.equals("-")) {
                int n = -1 * stack.pop() + stack.pop();
                stack.push(n);
            } else if (op.equals("*")) {
                int n = stack.pop() * stack.pop();
                stack.push(n);
            } else {
                stack.push(Integer.parseInt(op));
            }
        }

        System.out.println(stack.pop());
    }
}