#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 100005;
vector <int> v[NMAX];
bool ver[NMAX];
int capat,maxim;

int lungime=0;

void dfs(int node,int adancime)
{
    ver[node]=1;
    for(int i=0;i<v[node].size();i++)
    {
        int vecin = v[node][i];
        if(ver[vecin]==0)
        {
            dfs(vecin,adancime+1);
        }
    }
    if(adancime>maxim)
    {
        maxim=adancime;
        capat=node;
    }
}

int main()
{
    int n;
    fin >> n;
    int x,y;
    for(int i=1;i<=n;i++)
    {
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,1);
    for(int i=1;i<=n;i++) ver[i]=0;
    maxim=-1;
    dfs(capat,1);
    fout << maxim;
    return 0;
}