#include <bits/stdc++.h>

typedef long double ld;
typedef long long ll;
using namespace std;
int di[] = {1, 0, -1, -1, 0, 1, -1, 1};
int dj[] = {1, 1, 0, -1, -1, 0, 1, -1};
const ll oo = 1e18, MOD = 998244353;
const int N = 5e5 + 5, M = 1e6 + 5;
const ld PI = acos(-1.0), EPS = 1e-9;

//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

ll n, m, a[N];
vector<string> v[N];
string s;

//#define endl '\n'
int main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    //freopen("farm.in", "r", stdin);
    //memset(dp, -1, sizeof dp);
    cin >> n;
    int mx = 0, idx = 0;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        if (a[i] > mx) mx = a[i], idx = i;
        while (a[i]--) cin >> s, v[i].push_back(s);
    }
    cout << v[idx].size() << '\n';
    for (auto x:v[idx]) cout << x << '\n';
    return 0;
}