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.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Stack;

class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] str = br.readLine().split(" ");
		Stack<Integer> stack = new Stack<Integer>();

		for (int i = 0; i < str.length; i++) {
			if (str[i].equals("+")) {
				stack.push(stack.pop() + stack.pop());
			} else if (str[i].equals("-")) {
				int num01 = stack.pop();
				int num02 = stack.pop();
				stack.push(num02 - num01);
			} else if (str[i].equals("*")) {
				stack.push(stack.pop() * stack.pop());
			} else {
				stack.push(Integer.parseInt(str[i]));
			}
		}
		System.out.println(stack.pop());
	}
}