The Final One

Alex has some pending assignments to do. His teacher is very strict regarding summer assignments. Here goes the task : You are given two strings $S$ and $T$ of length $N$ and $M$ respectively. You need to find a string $X$ which is a prefix of $S$ as well as a suffix of $T$. You may perform none or atmost one of the following operations on the given strings - - Reverse the string $S$ before calcul