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){
        Scanner sc=new Scanner(System.in);
        String str;
        ArrayDeque<Integer> stack=new ArrayDeque<Integer>();
        while(sc.hasNext()){
            str=sc.next();
            if(str.equals("+")){
                stack.push(stack.pop()+stack.pop());
            }else if(str.equals("-")){
                stack.push((stack.pop()*-1)+stack.pop());
            }else if(str.equals("*")){
                stack.push(stack.pop()*stack.pop());
            }else{
                stack.push(Integer.parseInt(str));
            }
        }
        System.out.println(stack.pop());
    }
}
