#include <fstream>
#include <vector>
#include <queue>
#define NMax 100010

using namespace std;

int ans;
int n;
vector <int> G[NMax];
bool viz[NMax];
int d[NMax];
int last, level_last;

void Read()
{
    ifstream f ("darb.in");
    f>>n;
    for (int i = 1; i < n ; ++ i)
    {
        int x, y; f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    f.close();
}

void BFS(const int start)
{
    queue <int> Q;
    Q.push(start);
    viz[start] = true;
    d[start] = 1;
    while (!Q.empty())
    {
        int node = Q.front(); Q.pop();
        for (vector <int> :: iterator it = G[node].begin(); it!=G[node].end(); ++it)
            if (!viz[*it])
            {
                viz[*it] = true;
                d[*it] = d[node] + 1;
                if (d[*it] > level_last)
                {
                    level_last = d[*it];
                    last = *it;
                }
                Q.push(*it);
            }
    }
}

void BFS2(const int start)
{
    queue <int> Q;
    Q.push(start);
    viz[start] = false;
    for (int i = 1; i<=n; ++i)
        d[i] = 0;
    d[start] = 1;
    while (!Q.empty())
    {
        int node = Q.front(); Q.pop();
        for (vector <int> :: iterator it = G[node].begin(); it != G[node].end(); ++it)
            if (viz[*it])
            {
                viz[*it] = false;
                d[*it] = d[node] + 1;
                ans = max(ans, d[*it]);
                Q.push(*it);
            }
    }
}

inline void Write()
{
    ofstream g("darb.out");
    g<<ans<<"\n";
    g.close();
}


int main()
{
    Read();
    BFS(1);
    BFS2(last);
    Write();
    return 0;
}