下面程序是对n！进行唯一分解，横线处应该填入的是?
def unique_fac(n):
print(n, '=', end = '')
for i in range(2, n + 1):
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print(' {}*'.format(i), end = '')
n //= i
if n % i == 0 and i == n:
print(' {}'.format(i), end = '')
break
unique_fac(math.factorial(5))
