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.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        Deque<Integer> stack = new ArrayDeque<Integer>();

        while(sc.hasNext()) {
            String n = sc.next();
            if (n.equals("+")){
                int a = stack.pop()+stack.pop();
                stack.push(a);
            } else if (n.equals("-")){
                int x = stack.pop();
                int y = stack.pop();
                int a = y-x;
                stack.push(a);
            } else if (n.equals("*")) {
                int a = stack.pop()*stack.pop();
                stack.push(a);
            } else {
                stack.push(Integer.parseInt(n));
            }
            
        }
        System.out.println(stack.pop());
        
    }
}

