Trailing Zeros in a Combination

Given integers $n$ and $m$, determine how many consecutive zeros appear at the end of $\binom{n}{m}$ when it is written in decimal notation.

The first line contains two integers $n$ and $m$ separated by a space.

The constraints are $0 \le m \le n \le 2,000,000,000$ and $n \ne 0$.

Print the number of trailing zeros in $\binom{n}{m}$.