Number of zeros

Two integers $N$ and $K$ are given. Write a program zeros that finds the number of zeros in the decimal representation of $C\_N^K$.

$C\_N^K$ is the number of different ways to choose $K$ items from $N$ distinct items, ignoring their order.

$C\_N^K = \frac{N!}{K!(N-K)!}$

The first line of the standard input contains two integers $N$ and $K$.

The first line of the standard output must contain a single integer, the number of zeros.

• $1 ≤ N ≤ 1000$
• $0 ≤ K ≤ N$

The number $\frac{50!}{40!(50-40)!} = 10272278170$ contains two zeros.