#include <bits/stdc++.h>

using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
vector <int> G[100005];
queue <int> q;
int k,D;
bool viz[100002];
void dfs(int s, int d){
    viz[s] = 1;
    if(d > D){
        k = s;
        D = d;
    }
    for(int i = 0; i < G[s].size(); i++){
        int x = G[s][i];
        if(!viz[x]) dfs(x, d + 1);
    }
}
int main()
{
    int n,i,u,v;
    fin >> n;
    for(i = 1; i < n; i++){
        fin >> u >> v;
        G[u].push_back(v);
        G[v].push_back(u);
    }
    dfs(1,1);
    memset(viz,0,sizeof viz);
    dfs(k,1);
    fout << D;
    return 0;
}