Aliens Vs Humans

It's the year $2050!$, and the war has begun between aliens and humans. The aliens have placed mines in the battlefield, where the battlefield can be described as grid of size $n*m$, where $n$ denotes the number of rows numbered from $1$ to $n$ from top to bottom and $m$ denotes the number of columns numbered from $1$ to $m$ from left to right. However, the human army knows the positions of th