#include <fstream>
#include <vector>
using namespace std;
vector <int> V[100005];
int p[100005],retin=0,maxx=0;
void DFS(int a,int k)
{
    for(auto x:V[a])
    {
        if(p[x]==0)
        {
            p[x]=k;
            retin=k;
            maxx=max(maxx,k);
            DFS(x,k+1);
        }
    }
}
int main()
{
    ifstream cin("darb.in");
    ofstream cout("darb.out");
    int n,a,b;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>a>>b;
        V[a].push_back(b);
        V[b].push_back(a);
        retin=b;
    }
    DFS(retin,1);
    DFS(retin,1);
    cout<<maxx+1;
    return 0;
}