1 10 s 128 MB
Sifar is a malay word for zero or 0. In mathematics, trailing sifar is a sequence of 0s in the decimal representation of a number after which no other digits follow.
The number of trailing sifar in the decimal representation of N! (5 <= N <= 1,000,000) is simply the multiplicity of the prime factor 5 in N!. Given a decimal integer N, you are to find the number of trailing sifar for N! For example, 10! = 3,628,800. Thus, the number of trailing sifar for 10! is 2.
Each line of input contains an integer N where 5 <= N <= 1,000,000. The input is terminated with a line containing 0.
For each test case, the output contains a line in the format Case #x: M, where x is the case number (starting from 1) and M is the number of trailing sifar for N!
5 10 118 211 0
Case #1: 1 Case #2: 2 Case #3: 27 Case #4: 51