题目描述
n! = n × (n − 1) × (n − 2) × ... × 3 × 2 × 1
Is called the factorial of n. For example, the factorial of 12
12! = 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 479001600
And there are two consecutive 0s at the end.
Write a program that inputs the integer n and outputs the number of consecutive 0s at the end of n !. However, n is a positive integer less than or equal to 20000.
Input
Multiple data are given. Each piece of data is given n (n ≤ 20000) on one line. When n is 0, it is the last input.
The number of data does not exceed 20.
Output
For each data, output the number of 0s that are consecutively arranged at the end of n! On one line.
Example
Input
2
12
10000
0
Output
0
2
2499
输入格式
见题面
输出格式
见题面
样例输入
2
12
10000
0
样例输出
0
2
2499