// UUID: 6f3bea57-1287-4822-8684-0b6b4f37d6c1
#include <bits/stdc++.h>
using namespace std;

vector<vector<int>> graf;

pair<int, int> dfs(int u, int v) {
    int maxx=0, maxv=v;
    pair<int, int> c;
    for(auto x : graf[v]) {
        if(x != u){
            c = dfs(v, x);
            //cerr << c.first << ' ' << c.second << '\n';
            if(c.first > maxx) {
                maxx = c.first;
                maxv = c.second;
            }
        }
    }
    return {maxx+1, maxv};
}

int main() {
	int n, o = 0; cin >> n;
    graf.resize(n+1);
    for(int i=0;i<n;i++) {
        int a, f; cin >> a >> f;
        if(o == 0 || o == f) o = a;
        graf[a].push_back(f);
        graf[f].push_back(a);
    }

    //cerr << o;
    cout << dfs(o, o).second;

}