Alans First TH Class

Alan is member of Turing Hut the programming club of VNRVJIET. In his first class he was asked to draw the following pattern. The pattern is drawn on a n by m table. Denote c-th cell of r-th row as (r, c). The pattern starts at (1, 1), then it extends to (1, m), then goes down 2 rows to (3, m), then goes left to (3, 1) and so on. Your task is to draw this pattern for Alan: a empty cell shoul