#include <iostream>
#include <fstream>
#include <queue>
#include <vector>
#include <string.h>
std::ifstream in("darb.in");
std::ofstream out("darb.out");

using namespace std;
vector < int > v[100005];
bool viz[100005];int n,a,b,d[100005];
void dfs(int nod)
{
    viz[nod]=1;
    for(int i=0;i<v[nod].size();i++)
    {
        if(viz[v[nod][i]]==0)
        {
            d[v[nod][i]]=d[nod]+1;
            dfs(v[nod][i]);
        }

    }
}

int main()
{
    in>>n;
    for(int i=1;i<=n;i++)
    {
        in>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    d[1]=0;
    dfs(1);int maxim=1;
    for(int i=1;i<=n;i++)
    {
        if(d[maxim]<d[i])
            maxim=i;
    }
    memset(viz,0,sizeof(viz));
    memset(d,0,sizeof(d));
    dfs(maxim);
    maxim=-1;
    for(int i=1;i<=n;i++)
    {
        maxim=max(maxim,d[i]);
    }
    out<<maxim+1;
    return 0;
}