F. Factorial zeros
time limit per test
3 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

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!.

Examples
Input
6
Output
1
Input
24
Output
4
Note

In the first sample 6! = 720.

In the second sample 24! = 620448401733239439360000.