#include <fstream>
#include <vector>
using namespace std;
ifstream cin ("darb.in");
ofstream cout ("darb.out");
int n;
int rasp;
int bnod;
vector<int> g[100005];
void dfs(int nod,int dist,int parinte)
{
    if(dist>rasp)
    {
        bnod = nod;
        rasp = max(rasp,dist);
    }
    for(auto urm:g[nod])
    {
        if(urm==parinte)
            continue;
        dfs(urm,dist+1,nod);
    }
}
int main()
{
    cin >> n;
    for(int i=1;i<n;i++)
    {
        int a,b;
        cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    dfs(1,1,-1);
    dfs(bnod,1,-1);
    cout << rasp;
    return 0;
}