#include <fstream>
#include <vector>
using namespace std;
ifstream cin("darb.in");
ofstream cout("darb.out");
const int MAX = 1e5 + 1;
vector<int> adj[MAX];
int n, viz[MAX], rad = 1, lev, levmax;
void dfs(int nod) {
    viz[nod] = 1;
    ++lev;
    if(lev > levmax) {
        levmax = lev;
        rad = nod;
    }
    for(unsigned i = 0; i < adj[nod].size(); ++i) {
        int fiu = adj[nod][i];
        if(viz[fiu] == 0) {
            dfs(fiu);
        }
    }

    --lev;
}
int main()
{
    cin >> n;
    for(int i = 1; i < n; ++i) {
        int x, y;
        cin >> x >> y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    dfs(rad);
    for(int i = 1; i <= n; ++i) {
        viz[i] = 0;
    }
    dfs(rad);
    cout << levmax;
    return 0;
}