#include <iostream>
#include <stdio.h>
#include <vector>
#include <cstring>
#define NMax 100005
using namespace std;
vector<int> Graf[NMax];
int N,M,Max,Max1,dist[NMax],nodStart,x,y;
bool mark[NMax];

void Read()
{
    scanf("%d",&N);
    for(int i=1;i<=N;i++)
    {
        scanf("%d%d",&x,&y);
        Graf[x].push_back(y);
        Graf[y].push_back(x);
    }
}

void DFS1(int nod)
{
    for(vector<int>::iterator it=Graf[nod].begin();it!=Graf[nod].end();it++)
        if(mark[*it]==0)
        {
            mark[*it]=1;
            dist[*it]=dist[nod]+1;
            if(dist[*it]>Max)
            {
                Max=dist[*it];
                nodStart=*it;
            }
            DFS1(*it);
        }
}

inline void Clear()
{
    memset(mark,0,sizeof(mark));
}

void DFS2(int nod)
{
    for(vector<int>::iterator it=Graf[nod].begin();it!=Graf[nod].end();it++)
        if(mark[*it]==1)
        {
            mark[*it]=0;
            dist[*it]=dist[nod]+1;
            if(dist[*it]>Max1)
            {
                Max1=dist[*it];
                nodStart=*it;
            }
            DFS2(*it);
        }
}

int main()
{
    freopen("darb.in","r",stdin);
    ///freopen("darb.out","w",stdout);
    Read();
    dist[1]=mark[1]=1;

    DFS1(1);

    mark[nodStart]=dist[nodStart]=1;

    DFS2(nodStart);

    printf("%d ",Max1);
}