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);
		
		ArrayDeque<Integer> s = new ArrayDeque<>();
		
		while(sc.hasNext()){
			String str = sc.next();
			
			switch(str){
			case "+":
				s.push(s.pop() + s.pop());
				break;
			case "-":
				s.push(-1 * s.pop() + s.pop());
				break;
			case "*":
				s.push(s.pop() * s.pop());
				break;
			default:
				s.push(Integer.parseInt(str));
			}
		}
		
		System.out.println(s.pop());
	}
	
}

