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
lst = raw_input().split()
lst2 = []
for v in lst:
    if v == "+":
        lst2[len(lst2)-2] += lst2.pop()
    elif v == "-":
        lst2[len(lst2)-2] -= lst2.pop()
    elif v == "*":
        lst2[len(lst2)-2] *= lst2.pop()
    elif v == "/":
        lst2[len(lst2)-2] /= lst2.pop()
    else:
        lst2.append(int(v))
print lst2[0]