Competitions

# Number of zeroes in factorial

Find the number of zeros at the end of n! (n factorial).

#### Input

One integer n (1n2*109).

#### Output

Print the number of zeros at the end of n!

Time limit 1 second
Memory limit 128 MiB
Input example #1
7

Output example #1
1

Input example #2
12

Output example #2
2