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 -*-

list = map(str, raw_input().split())
num = []
for i in list:
    if i == '+':
        num[len(num)-2] += num.pop()
    elif i == '-':
        num[len(num)-2] -= num.pop()
    elif i == '*':
        num[len(num)-2] *= num.pop()
    else:
        num.append(int(i))
print num[0]