This grid of numbers has a region of contiguous squares, touching on their sides, containing the letters needed to spell the name of each SkyTrain station. (For example, NANAIMO only needs AIMNO to spell its name, and these letters can be found in a five-square, C-shaped cluster on the left half of the grid.) Determine how many squares can be safely erased so that this property still holds.
The names of the stations are:
22nd Street, 29th Avenue, Broadway, Burrard, Columbia, Edmonds, Granville, Joyce, King George, Main Street, Metrotown, Nanaimo, New Westminster, Patterson, Royal Oak, Scott Road, Stadium, Surrey Central, Waterfront