#include <stdio.h>
#include <iostream>
using namespace std;
const int N=100001,M=200001;

int vf[M],urm[M],lst[N];//listele
int coada[M],d[N];//in bfs
bool ver[N];
int fiu[N],scor[N];//in dfs
int nr,n,m,k;
int st=1;
int dr=0;

void adauga(int x, int y){
    nr++;
    vf[nr]=y;
    urm[nr]=lst[x];
    lst[x]=nr;

}

void bfs(int x)
{
    int p,y;


   coada[++dr]=x;
   for(int i=1;i<=n;i++) d[i]=-1;
   d[x]=0;
    while (st<=dr)
    {
        x=coada[st++];
        p=lst[x];
        while(p!=0){

            y=vf[p];
            if(d[y]==-1){
                d[y]=1+d[x];
                coada[++dr]=y;

            }
            p=urm[p];
        }
    }




}

void bfs2(int x)
{
    int p,y;

    st=1;
    dr=0;

    coada[++dr]=x;
    for(int i=1;i<=n;i++) d[i]=-1;
    d[x]=0;
    while (st<=dr)
    {
        x=coada[st++];
        p=lst[x];
        while(p!=0){

            y=vf[p];
            if(d[y]==-1){
                d[y]=1+d[x];
                fiu[y]=x;
                coada[++dr]=y;

            }
            p=urm[p];
        }
    }




}

void citre(){

    FILE *in;
    in=fopen("darb.in","r");
    fscanf(in,"%d",&n);
    int a,b;
    for(int i=1;i<=n;i++){
        fscanf(in,"%d%d",&a,&b);
        adauga(a,b);
        adauga(b,a);

    }
    fclose(in);

}


int main()
{

    FILE *out;
    out=fopen("darb.out","w");
    citre();

    bfs(1);//luam un nod oarecare si gasim cea mai indepartata frunza

    int maxim=-1,pmax;
    for(int i=1;i<=n;i++)
    if(maxim<d[i]){
        maxim=d[i];
        pmax=i;

    }
   // for(int i=1;i<=n;i++) cout<<d[i]<<" ";
    //cout<<pmax;
    bfs2(pmax);// gasim drumul care coincide cu drumul din nod spre cea mai indepartata frunza

    maxim=-1;
   for(int i=1;i<=n;i++)
    if(maxim<d[i]){
        maxim=d[i];
        pmax=i;

    }
    int p=pmax,cnt=0;


    while(fiu[p]!=0) {cnt++; p=fiu[p];}
    fprintf(out,"%d\n",cnt+1);
    /*
    fprintf(out,"%d ",pmax);
    while(fiu[pmax]!=0){
        fprintf(out,"%d ",fiu[pmax]);
        pmax=fiu[pmax];

    }
    fclose(out);
    */
    return 0;
}