the number of trailing zeros in a factorial of a given number - Ruby

Question

Having a little trouble trying calculate the number of trailing zeros in a factorial of a given number. This is one of the challenges from Codewars- can\'t get mine to pass.

Answer 1

n = int (raw_input())
count = 0
num = 1
for i in xrange(n+1):
        if i != 0:
            num = num * i

while(num >= 10):

    if num%10 == 0:
       count+=1
       num = num/10
    else:
        break

print count