#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long long ld;
const int MAX_N = 60;
const int MAX_M = 24;
ll spells[MAX_N + 1], cards[1ll << MAX_M];
int lg2[1 << MAX_M];
vector<int> mn;
int n, m;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n >> m;
for (int i = 1; i <= m; i++) {
int q;
cin >> q;
while (q--) {
int x;
cin >> x;
x--;
spells[i] |= (1ll << x);
}
}
for (int i = 2; i < (1ll << m); i++) {
lg2[i] = lg2[i >> 1] + 1;
}
for (int mask = 1; mask < (1 << m); mask++) {
int bit = lg2[(mask & -mask)];
cards[mask] = (cards[mask ^ (1ll << bit)] ^ spells[bit + 1]);
}
int answer = (1 << 30);
for (int mask = 0; mask < (1 << m); mask++) {
if (cards[mask] == (1ll << n) - 1) {
answer = min(answer, __builtin_popcountll(mask));
}
}
cout << answer << "\n";
for (int mask = 0; mask < (1 << m); mask++) {
if (cards[mask] == (1ll << n) - 1 && __builtin_popcountll(mask) == answer) {
vector<int> used;
for (int bit = 0; bit < m; bit++) {
if (mask & (1 << bit)) {
used.push_back(bit + 1);
}
}
if (mn.size() == 0 || used < mn) {
mn = used;
}
}
}
for (int it : mn) {
cout << it << " ";
}
return 0;
}
