Given a number find the number of trailing zeroes in its factorial.

Input Format

A single integer - N

Output Format

Print a single integer which is the number of trailing zeroes.

Input Constraints

1 ≤ N ≤ 1000

Problem Setter: Practo Tech Team

SAMPLE INPUT
10

SAMPLE OUTPUT
2

Explanation

10! = 3628800 has 2 zeros in the end.
import math

i = input()

if i >= 1 and i <=1000:
	f = math.factorial(i)
		
	l = len(str(f))	

	l1 = [f % (10**k) for k in range(1,l+1) if f % (10**k) == 0]
	print len(l1)
else:
	print "invalid input"