#include <bits/stdc++.h>
#define IOS ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define NMAX 100005

using namespace std;

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


vector <int> muchii[NMAX];
int lg[NMAX] , n , k;
bool viz[NMAX];

queue <int> Q;

void BFS(int nod)
{
    viz[nod] = 1;
    Q.push(nod);
    lg[nod] = 0;
    while(!Q.empty())
    {
        int curent = Q.front();
        Q.pop();
        for(int i = 0 ; i < muchii[curent].size() ; i ++)
            if(!viz[muchii[curent][i]])
            {
                viz[muchii[curent][i]] = 1;
                Q.push(muchii[curent][i]);
                lg[muchii[curent][i]] = lg[curent] + 1;
            }
    }
    int maxi = -1;
    for(int i = 1 ; i <= n ; i ++)
        if(maxi < lg[i])
        {
            maxi = lg[i];
            k = i;
        }
}

int main()
{
    IOS
    fin >> n;
    for(int i = 1 ; i <= n - 1 ; i ++)
    {
        int x , y;
        fin >> x >> y;
        muchii[x].push_back(y);
        muchii[y].push_back(x);
    }
    BFS(1);
    memset(lg , 0 , n + 1);
    memset(viz , 0 , n + 1);
    BFS(k);
    int maxi = -1;
    for(int i = 1 ; i <= n ; i ++)
        maxi = max(maxi , lg[i]);
    fout << maxi + 1;
    return 0;
}