End zeros solution doesn't let me go?

Hello ladies and gentlmen,

Could you please help me to pass the end zeros mission in elementary section? I use following code tested with success localy, but checkio doesn't let me go further:

#

def end_zeros(num: int) -> int: offset = -1 result = 0 while int(repr(num)[offset]) == 0: offset = offset-1 result += 1 return result

#

I receive following error: IndexError: string index out of range end_zeros, 4 <module>, 12

I've tested following code locally and the result was fine. I just added two lines: input on the beginning and print on the end to see the outcome.

num = int(input("Number to be checked: "))

def end_zeros(num: int) -> int: offset = -1 result = 0 while int(repr(num)[offset]) == 0: offset = offset-1 result += 1 return result

print (end_zeros(num))

Please help me to understand what is wrong.

Thanks in advance for your help!