#include<iostream>
#include<queue>
#include <vector>
using namespace std;
int way[2500][2500];
int used[110000];
int matr[2500][2500];
int maxs[10000];
int t = 0;
void dfs(int v, int n) {
    used[v] = 1;
    int maxx = 0;
    int max1 = 0;
    for (int i = 0; i < n; ++i) {
        if (!used[i] && matr[v][i]) {
            dfs(i, n);
            int pr_max = 0;
            for (int j = 0; j < n; ++j) {
                pr_max = max(pr_max, way[i][j]);
            }
            way[v][i] = pr_max + 1;
        }
    }
    for (int j = 0; j < n; ++j) {
        if (way[v][j] > maxx) {
            max1 = maxx; maxx = way[v][j];
        }
        else {
            if (way[v][j] > max1)
                max1 = way[v][j];
        }
    }
    int s_max = maxx + max1;
    maxs[t] = s_max;
    t++;
}
int main() {
#ifdef SYSTEM
    freopen("In.txt", "r", stdin);
    freopen("Out.txt", "w", stdout);
#endif
    int n;
    cin >> n;
    for (int i = 0; i < n - 1; ++i) {
        int a, b;
        cin >> a >> b;
        --a;
        --b;
        matr[a][b] = 1;
        matr[b][a] = 1;
    }
    for (int j = 0; j < n; ++j) {
        if (!used[j]) {
            dfs(j, n);
        }
    }
    int sup_max = 0;
    for (int k = 0; k < n; ++k) {
        if (maxs[k] > sup_max) sup_max = maxs[k];
    }
    cout << sup_max + 1;
    return 0;
}