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.ArrayDeque;
import java.util.Deque;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		Deque<Integer> numbers = new ArrayDeque<>();
		String str;
		int a = 0;
		int b = 0;

		while(scan.hasNext()) {
			str = scan.next();
			switch(str) {
				case "+":
					a = numbers.pop();
					b = numbers.pop();
					numbers.push(a + b);
					break;
				case "-":
					b = numbers.pop();
					a = numbers.pop();
					numbers.push(a - b);
					break;
				case "*":
					a = numbers.pop();
					b = numbers.pop();
					numbers.push(a * b);
					break;
				default:
					numbers.push(Integer.parseInt(str));
			}

		}

		System.out.println(numbers.peek());

	}
}

