#include <fstream>
#include <vector>
#include <bitset>
#define INF 0x3f3f3f3f
using namespace std;

ifstream is("darb.in");
ofstream os("darb.out");

using VI = vector<int>;
using VVI = vector<VI>;
using VP = vector<pair<int, int>>;
using VVP = vector<VP>;
using VPP = vector<pair<int, pair<int, int>>>;

int n, nr = 1, answ, na;
VVI g;
bitset<100001> ok;

void Read();
void Solve(int nod, int k);

int main()
{
    Read();
    Solve(1, 1);
    nr = 0;
    Solve(na, 1);
    os << answ;
    is.close();
    os.close();
    return 0;
}

void Solve(int nod, int k)
{
    ok[nod] = nr;
    if ( k > answ )
    {
        answ = k;
        na = nod;
    }
    for ( const auto &nodv : g[nod] )
        if ( ok[nodv] != nr )
            Solve(nodv, k + 1);
}

void Read()
{
    is >> n;
    g = VVI(n + 1);
    int x, y;
    for ( int i = 1; i < n; ++i )
    {
        is >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
}