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
rp = input().split()
n = len(rp)-1
i = 1
while n:
    if rp[i] in ('+', '-', '*'):
        i -= 1
        rp[i], rp[i+1] = rp[i+1], rp[i]
        rp[i-1] = str(eval(''.join(rp[i-1:i+2])))
        del rp[i:i+2]
        n -= 2
    else:
        i += 1
print(*rp)