#include <fstream>
#include <vector>
#include <queue>
#define DIM 100001
using namespace std;
ifstream fi("darb.in");
ofstream fo("darb.out");
int n;
int a,b;
vector<int> V[DIM];
int VIZ[DIM];
queue<int> Q;
int s,rez;
int main()
{
    fi>>n;
    for(int i=1;i<=n-1;i++)
    {
        fi>>a>>b;
        V[a].push_back(b);
        V[b].push_back(a);
    }
    Q.push(1);
    VIZ[1]=1;
    while(!Q.empty())
    {
        int v=Q.front();
        for(int i=0;i<V[v].size();i++)
            if(!VIZ[V[v][i]])
            {
                s=V[v][i];
                Q.push(V[v][i]);
                VIZ[V[v][i]]=1+VIZ[v];
            }
        Q.pop();
    }
    for(int i=1;i<=n;i++)
        VIZ[i]=0;
    VIZ[s]=1;
    Q.push(s);
    while(!Q.empty())
    {
        int v=Q.front();
        for(int i=0;i<V[v].size();i++)
            if(!VIZ[V[v][i]])
            {
                Q.push(V[v][i]);
                VIZ[V[v][i]]=1+VIZ[v];
                rez=VIZ[V[v][i]];
            }
        Q.pop();
    }
    fo<<rez;
    fi.close();
    fo.close();
    return 0;
}