C# has a typo in both the sample and full tests, 14.51 instead of 14:51.

I believe this solution is not correct anymore as it is throwing OverflowException for the last test with number 89. Type int should be replaced with long.

This solution is incorrect. For example if the first word is "la" and the second is "tola" it returns 2, but according to the instruction it should return -1, because 'If the second string isn't a valid rotation of the first string, the method returns -1."

The condition should be: second.Length != first.Length