#include <fstream>
#include <vector>
#define NMAX 100005
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
vector<int>G[NMAX],viz;
int rmax,nod;
void dfs(int u,int rk)
{
    int j,v;
    viz[u]=1;
    if(rk>rmax)
    {
        rmax=rk;
        nod=u;
    }
    for(j=0;j<G[u].size();++j)
    {
        v=G[u][j];
        if(viz[v]==0)
            dfs(v,rk+1);
    }
}
int main()
{
    int n,i,x,y;
    fin>>n;
    for(i=1;i<n;++i)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    viz.assign(n+1,0);
    rmax=-1;
    nod=1;
    dfs(1,0);
    viz.clear();
    viz.assign(n+1,0);
    dfs(nod,0);
    fout<<rmax+1<<"\n";
    return 0;
}