Factorial zeros
Description
You are given a positive integer n. Output the number of trailing zeros in n! (n! denotes a product of integers between 1 and n, inclusive).
The only line of input contains an integer n (1 ≤ n ≤ 1000000).
Output the number of trailing zeros in n!.
Input
The only line of input contains an integer n (1 ≤ n ≤ 1000000).
Output
Output the number of trailing zeros in n!.
Samples
6
1
24
4
Note
In the first sample 6! = 720.
In the second sample 24! = 620448401733239439360000.