#include <fstream>
#include <vector>

using namespace std;

/*ifstream cin ("input");
ofstream cout ("output");*/

ifstream cin ("darb.in");
ofstream cout ("darb.out");

vector < vector < int > > gr (100100);
vector < int > used (100100);

void dfs (int root , int dist , int &MAX , int &pos){
    if (MAX < dist){
        MAX = dist;
        pos = root;
    }
    for (auto &x : gr[root]){
        if (!used[x]){
            used[x] = true;
            dfs(x , dist + 1 , MAX , pos);
        }
    }
}

int main() {

    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int nodes;
    cin>>nodes;

    for (int i=1; i<nodes; i++){
        int a , b;
        cin>>a>>b;
        gr[a].push_back(b);
        gr[b].push_back(a);
    }

    int MAX = 1;
    int pos;
    dfs (1 , 1 , MAX , pos);

    for (auto &x : used){
        x = false;
    }

    MAX = 1;
    int inutil;
    dfs (pos , 1 , MAX , inutil);

    cout<<MAX;

    return 0;
}