#include <fstream>
#include <vector>

using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

int i,j,tati[100010],n,x,nod,y,Max,deaici,a1,a2;
vector<int> l[100010];

void dfstati(int nod,int nivel,int dela)
{
    if(Max<nivel)
    {
        Max=nivel;
        deaici=nod;
    }

    for(int i=0;i<l[nod].size();++i)
    {
        if(l[nod][i]!=dela)
            dfstati(l[nod][i],nivel+1,nod);
    }
}

int main()
{
    fin>>n;
    for(i=1;i<n;++i)
    {
        fin>>x>>y;
        l[y].push_back(x);
        l[x].push_back(y);
    }

    dfstati(1,1,0);
    Max=0;
    dfstati(deaici,1,0);
    fout<<Max;
    return 0;
}