#include <fstream>
#include <vector>
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
vector<int> arb[100001];
int n,diam,ult;
bool viz[100001];
void citire(){
 f>>n;
 int x,y;
 for(int i=1;i<n;i++){
  f>>x>>y;
  arb[x].push_back(y);
  arb[y].push_back(x);}}
void DFS(int x,int niv){
 if(niv>diam){diam=niv;ult=x;}
 viz[x]=1;
 for(auto it : arb[x])
  if(viz[it]==0)DFS(it,niv+1);}
int main(){
 citire();
 DFS(1,1);
 for(int i=1;i<=n;i++)viz[i]=0;
 DFS(ult,1);
 g<<diam;}