Farmer John let his N (1 <= N <= 250) cows conveniently numbered 1..N play in the field. The cows decided to connect with each other using cow-ropes, creating M (1 <= M <= N*(N-1)/2) pairwise connections. Of course, no two cows had more than one rope directly connecting them. The input shows pairs of cows c1 and c2 that are connected (1 <= c1 <= N; 1 <= c2 <= N; c1 != c2).
FJ instructed the cows to be part of a chain which contained cow #1. Help FJ find any misbehaving cows by determining, in ascending order, the numbers of the cows not connected by one or more ropes to cow 1 (cow 1 is always connected to herself, of course). If there are no misbehaving cows, output 0.
To show how this works, consider six cows with four connections:
1---2 4---5
\ |
\ | 6
\|
3
Visually, we can see that cows 4, 5, and 6 are not connected to cow 1.