public static long Solve(long NodeCount, long[][] edges, long StartNode, long EndNode)
{
Graph g = new Graph(NodeCount, edges);
for (long i = 0; i < edges.Length; i++)
{
g.addEdge(edges[i][0] - 1, edges[i][1] - 1);
g.addEdge(edges[i][1] - 1, edges[i][0] - 1);
}
return(g.ShortestPath(StartNode - 1, EndNode - 1));
}
static void Main(string[] args)
{
Graph graph = new Graph();
int N = Int32.Parse(Console.ReadLine());
for (int i = 0; i < N - 1; i++)
{
string str = Console.ReadLine();
int u = Int32.Parse(str.Split(' ')[0]);
int v = Int32.Parse(str.Split(' ')[1]);
graph.addEdge(u, v);
}
int x = Int32.Parse(Console.ReadLine());
graph.BFS(x);
}