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ADA Training September 7

Number of zeroes in factorial

Find the number of zeros at the end of n! (n factorial).

Input

One number n (1n2*109).

Output

The number of zeros at the end of n!

Time limit 1 second
Memory limit 128 MiB
Input example #1
7
Output example #1
1
Input example #2
12
Output example #2
2