#include <fstream>
#include <vector>
using namespace std;
ifstream cin("darb.in");
ofstream cout("darb.out");

int lastn, lg;
vector<int> v[100002];
bool viz[100002];

void dfs(int nod, int l) {
    viz[nod] = 1;
    if(l > lg) {
        lg = l;
        lastn = nod;
    }
    for(auto x : v[nod]) {
        if(!viz[x])
            dfs(x, l + 1);
    }
}

int main() {
    int n;
    cin >> n;
    for(int i = 1; i <= n - 1; i++) {
        int x, y;
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1, lg);
    lg = 0;
    for(int i = 1; i <= n; i++)
        viz[i] = 0;
    dfs(lastn, lg + 1);
    cout << lg << '\n';
    return 0;
}