#include <fstream>
#include <vector>
#define DIM 100010

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

vector<int> L[DIM];
int n, i, x, y, maxim;
void dfs(int nod, int niv, int tata) {
    if (niv > maxim) {
        maxim = niv;
        x = nod;
    }
    for (int i=0;i<L[nod].size();i++)
        if (L[nod][i] != tata)
            dfs(L[nod][i], niv+1, nod);
}

int main () {

    fin>>n;
    for (i=1;i<n;i++) {
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }

    maxim = 0;
    dfs(1,1,0);
    maxim = 0;
    dfs(x,1,0);
    fout<<maxim<<"\n";
    return 0;
}