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
hoge = list()
for elem in (elem for elem in input().split()):
    if elem == '+':
        elem = int(hoge.pop()) + int(hoge.pop())
    elif elem == '*':
        elem = int(hoge.pop()) * int(hoge.pop())
    elif elem == '-':
        elem = -1*int(hoge.pop()) + int(hoge.pop())
    hoge.append(elem)
print (elem)
