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
l = []
o = ["+", "-", "*"]
for i in input().split():
  if i in o:
    t = eval("{0}{1}{2}".format(l[-2], i, l[-1]))
    l.pop(-1)
    l[-1] = t
  else: l += [int(i)]
print(*l)
