Question 141
There are $n$ towns in a country. Some of the towns are connected with one-way roads, and between any two towns it is possible to have several roads in both directions. It is known that for any two towns $A$ and $B$ one can travel from $A$ to $B$, or from $B$ to $A$, or both. Find the minimum number of roads that have to be built such that one can travel in both directions between any two towns.