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){
        Deque<String> formula = new ArrayDeque<String>();
        Scanner scan = new Scanner(System.in);
        while(scan.hasNext()){
            String input = scan.next();
            if(input.equals("+")) input = String.valueOf(Integer.parseInt(formula.poll())+Integer.parseInt(formula.poll()));
            else if(input.equals("-")) input = String.valueOf(-1*Integer.parseInt(formula.poll())+Integer.parseInt(formula.poll()));
            else if(input.equals("*")) input = String.valueOf(Integer.parseInt(formula.poll())*Integer.parseInt(formula.poll()));
            formula.push(input);
        }
        System.out.println(formula.poll());
    }
}