#include <fstream>
#include <vector>

#define NMAX 100010

using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

void BFS(int x);

vector <int> C[2]; /// C[1] = C.nod... C[2] = C.distanta
vector <int> M[NMAX];
vector <bool> v;

int n, m;
int incep, dist, i, x, y;
int X[3];

int main()
{
    fin >> n;
    for(i = 1; i <= n; ++i)
        v.push_back(false);
    for(i = 1; i < n; ++i)
    {
        fin >> x >> y;
        M[x].push_back(y);
        M[y].push_back(x);
    }
    BFS(1);
    for(i = 0; i < v.size(); ++i)
        v[i] = false;
    C[1].clear();
    C[2].clear();
    BFS(incep);
    fout << dist << '\n';
    return 0;
}


void BFS(int x)
{
    int i;
    v[x] = true;
    int ic, sc;
    ic = sc = 0;
    C[1].push_back(x);
    C[2].push_back(1);
    while(ic <= sc)
    {
        X[1] = C[1][ic];
        X[2] = C[2][ic];
        ic++;
        for(i = 0; i < M[X[1]].size(); ++i)
            if(v[M[X[1]][i]] == false)
        {
            sc++;
            C[1].push_back(M[X[1]][i]);
            C[2].push_back(X[2]+1);
            v[M[X[1]][i]] = true;
        }
    }
    incep = C[1][sc];
    dist = C[2][sc];
}