#include <fstream>
#include <vector>
#include <queue>
#define NMAX 100001
#define pb push_back
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
int i,n,x,y,l[NMAX];
vector <int> A[NMAX];
int bfs(int nod)
{
    int u,i,nod2,dist=0;
    queue <int> Q;
    Q.push(nod);
    for(i=0;i<=n;i++) l[i]=0;
    l[nod]=1;
    while(!Q.empty())
    {
        nod=Q.front();
        Q.pop();
        for(i=0;i<A[nod].size();i++)
        {
            nod2=A[nod][i];
            if(l[nod2]==0)
            {
                Q.push(nod2);
                l[nod2]=l[nod]+1;
                if(l[nod2]>dist) {dist=l[nod2];u=nod2;}
            }
        }
    }
    return u;
}
int main()
{
    f>>n;
    for(i=1;i<=n-1;i++)
    {
        f>>x>>y;
        A[x].pb(y);
        A[y].pb(x);
    }
    g<<l[bfs(bfs(1))];
    return 0;
}