I have been facing this issue from past few contests my max(rating on CC is 1413)

I am talking purely about Codechef....... Whenever I try to solve 3rd question in div4 or 2nd question in div3 which usually falls under 1300-1400 question seems really simple and i code it well it passes all sample testcase and i submit it and it just passes 1 testcase saying wrong answer but really I just coded

OK....now you guys can think that ofcourse it fails when your logic is not right But I tried all possible answers and atlast I used all AI tools it just gives me the same code that i coded

Okkkkkkkkkkkkk let's just take this example this is the question link..... https://www.codechef.com/problems/SPLITPAIR?tab=statement

seems easy right we need to make sure that the number formed is even of even+even = even odd+odd = even so if even>=2 || odd >=2 ->YES else ->NO

So just what is wrong????