This grid shows the restaurants in Hamburg which have E la Carte units ("Prestos") installed in
them. The Ps in the grid represent restaurants with Prestos installed ("Prestorants"). Os
represent restaurants without prestos.

Alyssa P. Hacker from the E la Carte ops team wants to count the number of restaurants in the
largest contiguous rectangular block of Prestorants. What is the number that she comes up with?

Answer: __44__

top-left corner:     (15, 5742)
bottom-right corner: (18, 5752)
...where (0,0) is top-leftmost corner; right-down are positive x-y directions