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.*;

public class Main {
	public static void main(String[] args) {
		Stack<Long> stack = new Stack<Long>();
		Scanner scanner0 = new Scanner(System.in);
		Scanner scanner = new Scanner(scanner0.nextLine());
		scanner0.close();
		
		while (scanner.hasNext()) {
			if (scanner.hasNextLong()) {
				stack.push(scanner.nextLong());
			} else {
				long operand2 = stack.pop();
				long operand1 = stack.pop();
				String operator = scanner.next();
				
				if (operator.equals("+")) {
					stack.push(operand1 + operand2);
				} else if (operator.equals("-")) {
					stack.push(operand1 - operand2);
				} else {
					stack.push(operand1 * operand2);
				}
			}
		}
				
		scanner.close();
		
		System.out.println(stack.pop());
	}
} 

