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
#!/usr/bin/env python
#-*- coding: utf-8 -*-

S = []


def push(x):
    S.append(x)


def pop():
    return S.pop()


if __name__ == '__main__':
    for c in raw_input().split():
        if c == '+':
            push(pop() + pop())
        elif c == '-':
            b = pop()
            a = pop()
            push(a - b)
        elif c == '*':
            push(pop() * pop())
        else:
            push(int(c))
    print pop()
