#include <iostream>
#include <stack>
#include <fstream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");
int n, T=1, dt=0, viz2[100001], i, x, y;
vector<int> viz, v[100001];
queue<int> Q;
void bfs(int x)
{
    int K, G;
    Q.push(x); viz[x]=1;
    while(!Q.empty())
    {
        G=Q.front();
        for(int i=0;i<v[G].size();i++)
        {
            K=v[G][i];
            if(viz[K]==0)
            {
                viz[K] = viz[G] + 1;
                T=viz[K];

                Q.push(K);
            }
        }
        Q.pop();
    }
}
int main()
{
    in>>n;
    for(i=1;i<=n;i++)
    {
        in>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    viz = vector<int> (n+1, 0);
    bfs(1);
    viz = vector<int> (n+1, 0);
    dt=0;
    bfs(T);
    out<<T+1;
    return 0;
}