#include<bits/stdc++.h>
#define maxN 100005
using namespace std;
vector<int> v[maxN];
int n,dist[maxN],x,y;
bool seen[maxN];
deque<int> q;
inline void bfs(int nod)
{
    memset(seen,0,sizeof(seen));
    memset(dist,0,sizeof(dist));
    q.push_front(nod);
    seen[nod]=1;
    while(!q.empty())
    {
        int nod=q.front();
        q.pop_front();
        for(vector<int>::iterator it=v[nod].begin();it!=v[nod].end();it++)
        {
            if(!seen[*it])
            {
                dist[*it]=1+dist[nod];
                seen[*it]=1;
                q.push_back(*it);
            }
        }
    }
}
int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);
    for(int i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }


    bfs(1);
    int best=0;
    for(int i=1;i<=n;i++)
    {
        if(dist[i]>dist[best]) best=i;
    }

    bfs(best);
    int sol=0;
    for(int i=1;i<=n;i++)
        sol=max(sol,dist[i]);
    printf("%d\n",1+sol);
    return 0;
}