#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");

vector<int> graf[100002];
int last,maxim=-1,val,i,n,x,y,dist[100002];

void bfs(int start)
{
    int nod;
    for(i=1;i<=n;i++)
        dist[i]=-1;
    dist[start]=1;
    queue<int> q;
    q.push(start);
    while(!q.empty())
    {
        nod=q.front();
        q.pop();
        for(auto j:graf[nod])
        {
            if(dist[j]==-1)
            {
                q.push(j);
                dist[j]=dist[nod]+1;
                if(dist[j]>maxim)
                    maxim=dist[j], last=j;
            }
        }
    }
}


int main()
{
    fin>>n;
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    bfs(1);
    val=last;
    //fout<<val<<' ';
    maxim=-1;
    bfs(val);
    fout<<maxim;
    return 0;
}