def IsPrime(a):
    i = 2
    if a < 2:
        return 0
    while i * i <= a:
        if a % i == 0:
            return 0
        i += 1
    return a
#---------------------
while n > 1:
    if not (n % i) and IsPrime(i):
        if i in b:
            continue
        else:
            b[i] = 1
            n /= i
            while not (n % i):
                b[i] += 1
                n /= i
    i += 1