Gaitonde and Kailashpada

Gaitonde needs to conquer Kailashpada , but as you might already know in order to achieve his goal he needs to burn all the garbage dumps present throughout the kailashpada . Kailashpada can be represented as a grid of size $n * m$ , with rows numbered $1$ to $n$ from top to bottom, and columns $1$ to $m$ from left to right . Each cell is identified by a pair $( r ,c )$ , where $r$ represents $r$