#include <bits/stdc++.h>

using namespace std;

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

const int N = 100010;

int viz[N], maxim, ult, n;
vector<int> graf[N];

void dfs(int nod, int k)
{
    viz[nod] = 1;
    for(int i=0;i<graf[nod].size();i++)
    {
        int val = graf[nod][i];
        if(!viz[val])
        {
            if(maxim <= k+1)
            {
                maxim = k+1;
                ult=val;
            }
            dfs(val, k+1);
        }
    }
}

int main()
{
    fin>>n;
    for(int i=1;i<=n;i++)
    {
        int x,y;
        fin>>x>>y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }

    dfs(1,1);

    for(int i=1;i<=100000;i++)
        viz[i]=0;
    
    dfs(ult,1);

    fout<<maxim;

    return 0;
}