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
# -*- coding: utf-8 -*-

if __name__ == '__main__':

    stack = []
    line = input().split(" ")
    for s in line:
        if s.isdigit():
            stack.append(s)
        else:
            v2 = stack.pop()
            v1 = stack.pop()
            stack.append(str(eval(v1 + s + v2)))

    print(stack.pop())


