#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;
int n,m;
ll cur[24], des, ans;
ll bet(ll a, ll b) {
if (__builtin_popcount(a) < __builtin_popcount(b)) return a;
if (__builtin_popcount(a) > __builtin_popcount(b)) return b;
F0R(i,m) {
ll x = a&(1LL<<i);
ll y = b&(1LL<<i);
if (x < y) return b;
if (x > y) return a;
}
return a;
}
void search(int ind, ll c, ll use) {
if (c == des) {
ans = bet(ans,use);
return;
}
if (ind == m) return;
search(ind+1,c^cur[ind],use^(1LL<<ind));
search(ind+1,c,use);
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> m;
des = (1LL<<n)-1;
ans = (1LL<<m)-1;
F0R(i,m) {
int x; cin >> x;
F0R(j,x) {
int t; cin >> t; t --;
cur[i] ^= 1LL<<t;
}
}
search(0,0,0);
cout << __builtin_popcount(ans) << "\n";
F0R(i,m) if (ans&(1LL<<i)) cout << i+1 << " ";
}
/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/
