Sifar

Given $N$, print the largest $M$ such that $N!$ is divisible by $10^M$.

The input has several lines. Each line holds one integer $N$ with $5 \le N \le 10^6$. The last line holds $0$, and that line is not a test case.

For each test case, print the largest $M$ on its own line in the form Case #x: M. Here $x$ is the test case number and it starts at 1.

Sifar is said to mean zero in Malay.