Find last m non-zero digits of n!

factorial_info.py

# Find last m non-zero digits of n!
n, m = map(int, input().split())

cnt = 0
power = 5
while n // power > 0:
    cnt += n // power
    power *= 5

print(f"{n}! has {cnt} zeros.")

mod = 10**m
factorial = 1
for i in range(2, n+1):
    k = i
    while k % 5 == 0:
        k //= 5
    while k % 2 == 0 and cnt > 0:
        k //= 2
        cnt -= 1
    factorial = factorial * k % mod

s = str(factorial)
fill_zeros = "0"*(m-len(s))
print(f"Last {m} non-zero digits of {n}! = {fill_zeros}{s}")

You need to give a line input like "2019 3".