You are to write a program that receives a directed unweighted graph and finds all vertices of its strong-connected
component, containing given vertex S.
Input file format
Input file contains two integers N, M and S.
Vertices are numbered with integer numbers from 1 to N. M is the number of arcs.
Each of next M lines contain pair of integers — starting and ending vertices of some arc respectively.
There is at most one arc connecting two vertices in every direction.
Output file format
Output file must contain integer number T — amount of vertices in strong-connected component. After that, there must
be T integer numbers in ascending order — vertices of compontent themselves.