#include <bits/stdc++.h>

using namespace std;

ifstream f("darb.in");
ofstream g("darb.out");

int n,i,x,y,dist[100010];
pair<int,int> Max;
vector<int> v[100010];

void dfs(int nod)
{
    Max=max(Max,{dist[nod],nod});
    for(auto it:v[nod])
        if(!dist[it])
        {
            dist[it]=dist[nod]+1;
            dfs(it);
        }
    return ;
}

int main()
{
    f>>n;
    for(i=1;i<n;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dist[1]=1;dfs(1);
    memset(dist,0,sizeof(dist));
    dist[Max.second]=1;
    dfs(Max.second);
    g<<Max.first;
    return 0;
}