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
s=input().split()
d=[]
ans=0
for c in s:
    if c in '+-*':
        a,b=d.pop(),d.pop()
        d.append(str(eval(b+c+a)))
    else:
        d.append(c)
print(d[0])
