Unreachability Cost

The country of Chefland has $N$ cities and $M$ **unidirectional** roads between these cities. You plan to visit Chefland as a tourist, but you haven't yet decided which cities to visit or what your budget will be. However, you do know that you'd like to use the roads as much as possible. Let's call a pair of cities $(u, v)$ *disconnected*, if either there is no path from city $u$ to city $v$ u