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);
        Stack<Long> st = new Stack<Long>();

        while (sc.hasNext()){
            String s = sc.next();
            switch (s){
                case "+":
                    st.push(st.pop()+st.pop());
                    break;
                case "-":
                    st.push(-st.pop()+st.pop());
                    break;
                case "*":
                    st.push(st.pop()*st.pop());
                    break;
                default:
                    st.push(new Long(s));
            }
        }
        System.out.println(st.pop());
    }
}