Expect Some Damage

A country can be represented as a grid of $n$ rows and $m$ columns where there are total $n*m$ cities. These cities are about to face bomb attacks. There are $q$ such bombs and we know the probability of each bomb attack and on which cities will it affect. You have given $x1,y1$ and $x2,y2$ and the probability of a drop of bomb. The bomb will affect all the cities in rectangle bound by $x1,y1$ and