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 {
	public static int top = 0;
	public static int[] stack = new int[200];
	
	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		String[] k = (stdIn.nextLine()).split(" ");
		
		for (int i = 0; i < k.length;i++) {
			if (k[i].equals("+")) {
				int b = pop();
				int a = pop();
				push(a + b);
			}
			else if (k[i].equals("-")) {
				int b = pop();
				int a = pop();
				push(a - b);
			}
			else if (k[i].equals("*")) {
				int b = pop();
				int a = pop();
				push(a * b);
			}
			else
				push(Integer.parseInt(k[i]));
		}
		
		System.out.println(pop());
	}
	
	public static void push(int x) {
		stack[++top] = x;
	}
	
	public static int pop() {
		top--;
		return stack[top+1];
	}
}