#include <bits/stdc++.h>
#define int long long
#define POP __builtin_popcount
#define iamaperson int main() {\
preprocess();\
int t = 1; while (t--) solve();\
}
using namespace std;
void preprocess() {} // just in case!!!!1
void solve() {
int n, m; cin >> n >> m;
vector<int> mgc(m);
for (int i = 0; i < m; ++i) {
int q; cin >> q;
for (int _ = 0; _ < q; ++_) {
int x; cin >> x;
mgc[i] |= 1LL<<(x-1);
}
}
vector<int> pot;
for (int i = 0; i < 1LL<<m; ++i) {
int x = 0;
for (int j = 0; j < m; ++j) if (i&(1<<(m-1-j))) {
x ^= mgc[j];
}
if (x == (1LL<<n)-1) pot.push_back(i);
}
int ans = *min_element(pot.begin(), pot.end(), [&](const int &a, const int &b){ return POP(a) < POP(b) ? 1 : a > b; });
cout << POP(ans) << '\n';
for (int j = 0; j < m; ++j) if (ans&(1<<(m-1-j))) cout << 1+j << ' ';
}
#undef int
iamaperson
