# include <fstream>
# include <vector>
# include <cstring>
using namespace std;
ifstream fi("darb.in");
ofstream fo("darb.out");
vector <int> G[100001];
int n,nr,capat;
int viz[100001];

void DFS (int x, int niv)
{
    viz[x]=1;
    if (niv > nr) {nr=niv; capat=x;}
    for (auto & y : G[x])
        if (! viz[y])  DFS (y, niv+1);
}

void ReadGraph()
{
    fi>>n;
    for (int i=1,x,y; i<n; ++i)
    {
        fi>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}
int main ()
{
    ReadGraph();
    DFS (1, 1);
    memset (viz, 0, sizeof(viz));
    DFS (capat, 1);
    fo<<nr<<"\n";
    return 0;
}