Estate In Hand

There are $N$ businessmen from $0$ to $N - 1$ who are ready to invest in real estate. Some of them are friends and thus form a group. You have been given $M$ facts that businessmen $u$ and $v$ are friends. The same fact can be given multiple times. If $X$ and $Y$ are friends and $Y$ and $Z$ are friends, then it is always true that $X$ and $Z$ are also friends. You have been given $N$ real estate