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;

public class Main {
	void run() {
		Scanner scan = new Scanner(System.in);
		Stack<Integer> stack = new Stack<Integer>();
		while (scan.hasNext()) {
			String token = scan.next();
			switch (token) {
			case "+": {
				int v1 = stack.pop();
				int v2 = stack.pop();
				stack.push(v2 + v1);
				break;
			}
			case "-": {
				int v1 = stack.pop();
				int v2 = stack.pop();
				stack.push(v2 - v1);
				break;
			}
			case "*": {
				int v1 = stack.pop();
				int v2 = stack.pop();
				stack.push(v2 * v1);
				break;
			}
			default: {
				stack.push(Integer.valueOf(token));
				break;
			}
			}
		}
		System.out.println(stack.pop());
	}
	public static void main(String[] args) {
		new Main().run();
	}
}

