Trailing Zeros

Explanation

Here, we are given a number n and we are required to find out the number of trailing zeros in n!.

This can be found by counting the number of times 5 appears in the prime factorization of n!.
And the answer to that is floor(n/5) + floor(n/25) + floor(n/125) + ...

Code

n = int(input())
print(sum(n // (5 ** i) for i in range(1, 14)))