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;

public class Main {

	static int top;
	static int[] S = new int[1000];

	public static void push(int x) {
		top++;
		S[top] = x;
	}

	public static int pop() {
		top--;
		return S[top + 1];
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a, b;
		String s;
		top = 0;
		while (sc.hasNext()) {
			s = sc.next();
			if (s.charAt(0) == '+') {
				b = pop();
				a = pop();
				push(a + b);
			} else if (s.charAt(0) == '-') {
				b = pop();
				a = pop();
				push(a - b);
			} else if (s.charAt(0) == '*') {
				b = pop();
				a = pop();
				push(a * b);
			} else {
				push(Integer.parseInt(s));
			}
		}
		System.out.println(pop());
		sc.close();
	}
}

