#include<fstream>
#include<queue>
#include<vector>
using namespace std;
ifstream cin("bfs.in");
ofstream cout("bfs.out");
int n,m,s,d[100001];
vector<int>a[100000001];
int main()
{
    cin>>n>>m>>s;
    for(int i=0;i<n-1;i++)
    {
        int x,y;
        cin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    queue <int>q;
    for(int i=1;i<=n;i++)
    {
        d[i]=-1;
    }
    d[s]=0;
    q.push(s);
    while(!q.empty())
    {
        int x=q.front();
        q.pop();
        for(auto y:a[x])
        {
            if(d[y]==-1)
            {
                d[y]=1+d[x];
                q.push(y);
            }
        }
    }
}