#include<fstream>
#include<vector>
#include<cstring>
using namespace std;
ifstream eu("darb.in");
ofstream tu("darb.out");
#define Nmax 100005
int N,Sol,SolN;
vector<int>G[Nmax];
bool Use[Nmax];
void DFS(int nod,int lvl)
{
    if(lvl>Sol)
    {
        Sol=lvl;
        SolN=nod;
    }
    Use[nod]=1;
    for(vector<int>:: iterator it=G[nod].begin();it!=G[nod].end();it++)
        {
        if(!Use[*it])
            DFS(*it,lvl+1);
        }
}
int main()
{
    eu>>N;
    while(N--)
    {
        int x,y;
        eu>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    DFS(1,0);
    Sol=0;
    memset(Use,0,Nmax);
    DFS(SolN,0);
    tu<<Sol+1<<"\n";
    return 0;
}