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.Scanner;

public class Main {

    public static void main(String[] args) {
        try (Scanner in = new Scanner(System.in)) {
            solve(in);
        }
    }

    private static void solve(Scanner in) {
        int[] stack = new int[200];
        int idx = 0;
        while (in.hasNext()) {
            String next = in.next();
            if (next.equals("+")) {
                stack[idx - 2] = stack[idx - 2] + stack[idx - 1];
                idx--;

            } else if (next.equals("-")) {
                stack[idx - 2] = stack[idx - 2] - stack[idx - 1];
                idx--;

            } else if (next.equals("*")) {
                stack[idx - 2] = stack[idx - 2] * stack[idx - 1];
                idx--;

            } else {
                int n = Integer.valueOf(next);
                stack[idx++] = n;
            }
        }
        System.out.println(stack[0]);
    }
}