You will be given a string and you task is to check if it is possible to convert that string into a palindrome by removing a single character. If the string is already a palindrome, return "OK". If it is not, and we can convert it to a palindrome by removing one character, then return "remove one", otherwise return "not possible". The order of the characters should not be changed.
For example:
solve("abba") = "OK". -- This is a palindrome
solve("abbaa") = "remove one". -- remove the 'a' at the extreme right.
solve("abbaab") = "not possible".
More examples in the test cases.