Yes, you're right, then i rewrite my solution

OP solved it, closing!

Yes, you're right, then i rewrite my solution. Thanks for help

No, it is not "in an absolutely random time". It is always. For "abcb", your solution always return "cb" instead of "bc". Your solution has a bug, and handles some inputs incorrectly. You can also check "abc abc".

But in some moments, in an absolutly random time it may be s='cb'

You need to check exactly, because for s="abcb", your solution does not return "bc" (as it should), but something else.

What will your solution return for string s="abcb"?

It is very difficult to tell why your code is wrong without seeing your code, or even without knowing what language you are trying to solve.

Hello everyone, I have a problem, i don't know why, but with true solution, each time, when i try to answer, randow number of tests be wrong.
Like 25 true answer, 21 wrong OR 40 true, 6 wrong.
And symbols in string replaced in random place, first and last places removed, but in some tests, like "khgjhbkjgjhb" answer is "hghhbkjgjj" but true answer is "hgjhbkjgjh".
What's a problem?

hi

hello in the simple and random test there is a two-character test

hello you don't need if
kata accepts only return as a response, print makes no sense.
the conditions explicitly say that you don't have to worry about the length of strings.

hi

they say not to worry about undefined etc doesnt told us about if there are two char only string xd