# Task
 Mobius function - an important function in number theory. For each given n, it only has 3 values:
```
0  -- if n divisible by square of a prime. Such as: 4, 8, 9
1  -- if n not divisible by any square of a prime 
        and have even number of prime factor. Such as: 6, 10, 21
-1 -- otherwise. Such as: 3, 5, 7, 30```
Your task is to find mobius(`n`)
# Input/Output
 - `[input]` integer `n`
 `2 <= n <= 1e12`
 - `[output]` an integer
def mobius(n):
    s, p, m = 0, 2, n ** .5
    while p <= m:
        if not n % p:
            s += 1
            n //= p
        if not n % p:
            return 0
        p += 1
    if n > 1:
        s += 1
    return 1 - s % 2 * 2
def mobius(n):
    s, p, m = 0, 2, n ** .5
    while p <= m:
        if not n % p:
            s += 1
            n //= p
        if not n % p:
            return 0
        p += 1
    if n > 1:
        s += 1
    return 1 - s % 2 * 2