#include<fstream>
#include<queue>
#include<vector>
#include<cstring>
using namespace std;
int n,niv[100001],ultim,diam;
vector<int> v[100001];
queue<int> q;
ifstream fin("darb.in");
ofstream fout("darb.out");
void citire()
{
    int x,y;
    fin>>n;
    for(int i=1;i<n;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

void dfs(int nod)
{
    memset(niv,0,sizeof(niv));
    q.push(nod);
    niv[nod]=1;
    while(!q.empty())
    {
        nod=q.front();
        q.pop();
        for(int i=0;i<v[nod].size();i++)
        {
            if(niv[v[nod][i]]==0)
            {
                diam=niv[v[nod][i]]=niv[nod]+1;
                q.push(v[nod][i]);
                ultim=v[nod][i];
            }
        }
    }
}

int main()
{
    citire();
    dfs(1);
    dfs(ultim);
    fout<<diam;
    return 0;
}