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;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

class Main {public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		
		Stack<Integer> stack = new Stack<Integer>();
		Pattern p = Pattern.compile("[0-9]+");
		
		while(sc.hasNext()) {
			String s = sc.next();
			Matcher m = p.matcher(s);
			if(m.find()) stack.push(Integer.parseInt(s));
			else if(s.equals("+")) stack.push(stack.pop() + stack.pop());
			else if(s.equals("-")) stack.push((-stack.pop() + stack.pop()));
			else if(s.equals("*")) stack.push(stack.pop() * stack.pop());
		}
		
		System.out.println(stack.pop());
	}
}
