Attempt

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Problem

Given an integer ~N~. Please find the number of trailing zeros in the factorial ~N!~.

For example ~20! = 2,432,902,008,176,640,000~ and it have ~4~ trailing zeros.

Input

Single line contain an integer ~N~.

Output

Print a single positive integer is the trailing zeros of ~N!~.

Constraints

~1 \leq N \leq 10^9~.

Sample