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).

Input

The only line of input contains an integer n (1 ≤ n ≤ 1000000).

Output

Output the number of trailing zeros in n!.

见题面 Input 部分

见题面 Output 部分

In the first sample 6! = 720.

In the second sample 24! = 620448401733239439360000.