#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

int n, l1[100003], l2[100003], maxi, nod;
vector<int> graph[100005];
queue<int> Q;

ifstream f("darb.in");
ofstream g("darb.out");


void part1() {
    Q.push(1);
    l1[1] = 1;
    maxi = 1;
    nod = 1;
    while (!Q.empty()) {
        int node = Q.front();
        Q.pop();
        for (auto &v:graph[node])
            if (!l1[v]) {
                l1[v] = l1[node] + 1;
                Q.push(v);
                if (maxi < l1[v]) {
                    maxi = l1[v];
                    nod = v;
                }
            }
    }
}

void part2() {
    Q.push(nod);
    l2[nod] = 1;
    maxi = 1;
    while (!Q.empty()) {
        int node = Q.front();
        Q.pop();
        for (auto &v:graph[node])
            if (!l2[v]) {
                l2[v] = l2[node] + 1;
                Q.push(v);
                maxi = max(l2[v], maxi);
            }
    }
}


int main() {
    f >> n;
    int x, y;
    for (int i = 0; i < n - 1; i++) {
        f >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    part1();
    part2();
    g << maxi;
    return 0;
}