#include <fstream>
#include <vector>

using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

int n, a, b;
int visit1[100001], visit2[100001], nod, d;
vector <int> v[100001];

void dfs1(int i, int l){
    visit1[i] = 1;
    for(int j=0; j<v[i].size(); j++)
        if(visit1[v[i][j]] == 0)
            dfs1(v[i][j], l+1);
    if(l > d){
        d = l;
        nod = i;
    }
}

void dfs2(int i, int l){
    visit2[i] = 1;
    for(int j=0; j<v[i].size(); j++)
        if(visit2[v[i][j]] == 0)
            dfs2(v[i][j], l+1);
    if(l > d)
        d = l;
}

int main()
{
    fin >> n;
    for(int i=1; i<n; i++){
        fin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs1(1, 1);
    dfs2(nod, 1);
    fout << d;
    return 0;
}