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
from collections import deque

ope = ["+","-","*","/"]

l = input().split()

d = deque()
while l:
    x = l.pop(0)
    if x in ope:
        n1 = d.pop()
        n2 = d.pop()
        val = str(n2)+x+str(n1)
        d.append(eval(val))
    else:
        d.append(x)
    
print(d.pop())
