#include <fstream>
#include <vector>
#include <queue>
#include <cstring>
using namespace std;

ifstream F("darb.in");
ofstream G("darb.out");

const int N = 100010;

vector<int> v[N];
int n,dist[N],x,y,mk[N];

int bfs(int x)
{
    memset(mk,0,sizeof(mk));

    queue<int> q;
    q.push(x);
    dist[x] = 0;

    int lst = 0;

    while ( !q.empty() )
    {
        int x = q.front();
        mk[x] = 1;
        q.pop();
        lst = x;

        for (int i=0;i<int(v[x].size());++i)
        {
            int y = v[x][i];

            if ( mk[y] ) continue;

            dist[y] = dist[x] + 1;
            q.push(y);
        }
    }
    return lst;
}

int main()
{
    F>>n;
    for (int i=1;i<n;++i)
    {
        F>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    x = bfs(1);
    y = bfs(x);
    //G<<x<<' '<<y<<'\n';
    G<<dist[y]+1<<'\n';
}