p =: verb : '-:y*_1+3*y' wa =: p 1+i.10000 isP =: e.&wa sums =: isP +/~ wa difs =: isP -/~ wa heh =: sums *. difs row =: I. +/"1 heh col =: I. +/ heh problem44 =: x: (p 1+row) - (p 1+col)