Dineu

/* [A][M][C][B][N] / [K][R][I][P][6][8] */
#include <bits/stdc++.h>
#include <unordered_map>
using namespace std;
typedef long long ll;
const char sp = ' ', nl = '\n';
const int MOD = 9973;
ifstream fin("dineu.in");
ofstream fout("dineu.out");
vector<bool> f;
vector<int> v;
bool FOUND = 0;
void gensubmult(int idx) {
    if (FOUND) return;
    if (idx == f.size()) {
        int ok = 1;
        for (int i = 0; i < f.size(); ++i)
            if (f[i])
                for (int j = 0; j < f.size(); ++j)
                    if (f[j])
                        ok &= bool(v[i] & v[j]);
        if (ok) {
            FOUND = 1;
            int ans = 0;
            for (int i = 0; i < f.size(); ++i)
                ans += f[i];
            fout << ans << nl;
            for (int i = 0; i < f.size(); ++i)
                if (f[i])
                    fout << i + 1 << sp;
        }
    }
    else {
        f[idx] = 1;
        gensubmult(idx + 1);
        f[idx] = 0;
        gensubmult(idx + 1);
    }
}


int main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    int n, l;
    fin >> n >> l;
    v.resize(n), f.resize(n);
    for (int i = 0; i < n; ++i) {
        int k, x;
        fin >> k;
        while (k--) {
            fin >> x;
            v[i] += 1 << x;
        }
    }
    gensubmult(0);
}