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;
import java.util.Stack;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        Stack<Integer> S = new Stack<>();

        String input = sc.nextLine();
        String[] input_ = input.split(" ");
        sc.close();

        for(int i = 0; i < input_.length; i++){
            if(input_[i].equals("+")){
                int x = S.pop();
                int y = S.pop();
                S.push(y + x);
            }else if(input_[i].equals("-")){
                int x = S.pop();
                int y = S.pop();
                S.push(y - x);
            }else if(input_[i].equals("*")){
                int x = S.pop();
                int y = S.pop();
                S.push(y * x);
            }else{
                S.push(Integer.parseInt(input_[i]));
            }
        }
        System.out.println(S.firstElement());
    }
}

