#include <iostream>
#include <fstream>
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");

struct nod{
 int val;
 nod* next;
};

nod* arb[100001];
int n,diam,ult;
bool viz[100001];


void add_nod(int x,int val){
 nod* p=new nod;
 p->val=val;
 p->next=arb[x];
 arb[x]=p;
}

void citire(){
 f>>n;
 int x,y;
 for(int i=1;i<n;i++){
  f>>x>>y;
  add_nod(x,y);
  add_nod(y,x);
 }
}

void DFS(int x,int niv){
 if(niv>diam){diam=niv;ult=x;}
 viz[x]=1;
 for(nod* p=arb[x];p!=NULL;p=p->next)
  if(viz[p->val]==0)DFS(p->val,niv+1);
}

int main(){
 citire();
 DFS(1,1);
 for(int i=1;i<=n;i++)viz[i]=0;
 DFS(ult,1);
 g<<diam;
}