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.io.*;
import java.util.Arrays;
import java.util.*;

class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] str = (br.readLine()).split(" ");
		Deque<Integer> stack = new ArrayDeque<Integer>();
		for (int i = 0; i<str.length ; i++ ) {
			if (str[i].equals("+")) {
				int	a = stack.pop();
				int	b = stack.pop();
				int	c = a+b;
				stack.push(c);	
			}else if(str[i].equals("-")){
				int	a = stack.pop();
				int	b = stack.pop();
				int	c = b-a;
				stack.push(c);	
			}else if (str[i].equals("*")) {
				int	a = stack.pop();
				int	b = stack.pop();		
				int	c = a*b;
				stack.push(c);	
			}else{
				stack.push(Integer.parseInt(str[i]));
			}
		}
		System.out.println(stack.pop());
	}
}