#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
#include <algorithm>
#include <utility>
#include <cmath>
#include <map>
#include <deque>
#include <vector>
#include <set>
#include <queue>
using namespace std;
 
ifstream fin("darb.in");
ofstream fout("darb.out");
 
const int MAX_SIZE = 100005;
vector<int> graph[MAX_SIZE];
int maximums[MAX_SIZE], noMax = 0;
int result = 0;
int lastPeak = 0;

void findMaximumDistances(int start) {
    int distances[MAX_SIZE];
    memset(distances, -1, MAX_SIZE);
    distances[start] = 0;
    queue<int> positions;
    positions.push(start);
    int maximum = 0;
    while (!positions.empty()) {
        int currentPeak = positions.front();
        positions.pop();
        if (1 == graph[currentPeak].size()) {
            lastPeak = currentPeak;
        }
        for (int i = 0; i < graph[currentPeak].size(); ++i) {
            int nextPeak = graph[currentPeak][i];
            if (distances[nextPeak] == -1) {
                distances[nextPeak] = distances[currentPeak] + 1;
                maximum = max(maximum, distances[nextPeak]);
                positions.push(nextPeak);
            }
        }
    }
    result = max(result, maximum);
}
 
int main() {
    int peaks;
    fin >> peaks;
    for (int i = 1; i <= peaks - 1; ++i) {
        int start, end;
        fin >> start >> end;
        graph[end].push_back(start);
        graph[start].push_back(end);
    }
    findMaximumDistances(1);
    findMaximumDistances(lastPeak);
    fout << result + 1;
    return 0;
}

/*
 
 10
 1 2
 2 3
 3 4
 4 5
 5 6
 6 7
 7 8
 8 9
 9 10 -> 18 NU
 
 
 11
 1 2
 1 3
 1 4
 2 5
 3 6
 4 7
 5 8
 5 9
 6 10
 10 11 -> 8 ok
 
 
12
 11 1
 1 2
 2 4
 11 10
 10 3
 3 7
 11 9
 9 5
 5 12
 5 6
 11 8 -> 7 ok
 
 
 */