#include <fstream>
#include <string.h>
#include <vector>
#include <queue>
#include <limits.h>

#define nMax 100001
#define lgMax 19
#define pb push_back
#define INF INT_MAX
#define bit(i) i&(-i)
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
int n, last;
int viz[nMax];
vector<int> G[nMax];
queue<int> Q;
void read()
{
    int a, b;
    fin>>n;

    for(int i=2;i<=n;i++)
    {
        fin>>a>>b;
        G[a].pb(b);
        G[b].pb(a);
    }
}
void bfs(int S)
{
    memset(viz, -1, sizeof(viz));
    viz[S]=0;

    for(Q.push(S);!Q.empty();)
    {
        int node=Q.front();
        Q.pop();

        for(vector<int>::iterator it=G[node].begin();it!=G[node].end();it++)
        {
            int fiu=*it;

            if(viz[fiu]==-1)
            {
                Q.push(fiu);
                viz[fiu]=viz[node]+1;
                last=fiu;
            }
        }
    }
}
void solve()
{
    bfs(1);
    bfs(last);
    fout<<viz[last]+1;
}
int main()
{
    read();
    solve();
    return 0;
}