#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream f("aria.in");
ofstream g("aria.out");

int N, x, y, prec, diametru, D[100002];
queue < int > Q;
vector < int > G[100002];

void bfs(int sursa)
{
    Q.push(sursa);
    for (int i=1; i<=N; ++i) D[i]=0;
    while (Q.size())
    {
        int nod=Q.front(); Q.pop();
        vector <int>::iterator it=G[nod].begin();
        for (; it!=G[nod].end(); ++it)
            if (D[*it]==0)
            {
                D[*it]=D[nod]+1, Q.push(*it), prec=*it;
                if (D[*it]>diametru) diametru=D[*it];
            }
    }
}

int main()
{
    f>>N;
    for (int i=1; i<N; ++i)
        f>>x>>y, G[x].push_back(y), G[y].push_back(x);
    bfs(1); bfs(prec); g<<diametru<<'\n';
    return 0;
}