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
from operator import add, sub, mul

op_dict = {'+': add, '-': sub, '*': mul}

def calcurate(list_):
    s = []
    for l in list_:
        if l.isdigit():
            s.append(int(l))
        elif l in ['+', '-', '*']:
            a = s.pop()
            b = s.pop()
            s.append(op_dict[l](b, a))
    return s[0]



def main():
    inputs = raw_input().split()
    print calcurate(inputs)


if __name__ == '__main__':
    main()