Tony and String Queries

Today, Tony is facing yet another problem on strings with queries. He has a grid containing lowercase english characters with $n$ rows and $m$ columns. Now Tony has to answer $q$ queries in which he is given coordinates of a point on grid $(r, c)$ with a string $s$. This point is actually the top left corner of a square of area $A$. Tony needs to find the minimum area $A$ of this square such that