Number of zeros in the factorial X97024

Implement the function

    int nzeros_fact(int x);

which returns the number of ending zeroes in its factorial.

Take into account that ending zeros correspond to powers of $5$ and, for each $k$, the corresponding number of zeroes is $$\sum_{i>0} x/5^i.$$

Input

Input consists of an integer number.

Precondition

It holds $0 <$ @x@$< 10^9$.

Observation

You only need to submit the required procedure; your main program will be ignored.