#include <bits/stdc++.h>
using namespace std;
#define print(l) for(auto i:l) cout<<i<<" ";cout<<endl;
#define input(t,l,n) vector<t>l(n);for(int i = 0;i<n;i++)cin>>l[i];
#define int long long
#define pb push_back
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define all(l) l.begin(),l.end()
#define pii pair<int,int>
#define fi first
#define se second
const int M = 1e9+7;
const int inf = 1e18;
int bp(int x, int y, int p){
int res = 1;
x = x % p;
while (y > 0) {
if (y & 1)
res = (res * x) % p;
y = y >> 1;
x = (x * x) % p;
}
return res;
}
int MI(int n, int p){
return bp(n, p - 2, p);
}
int mul(int x,int y, int p){
return x * 1ull * y % p;
}
int di(int x,int y, int p){
return mul(x, MI(y, p), p);
}
int n , m , k , q;
void solve(int testcase_number){
cin>>n>>m;
int mx = (1ll<<m);
vector<bitset<70>> mask(mx+1);
vector<vector<int>>ans(mx+1);
vector<bitset<70>>d;
bitset<70>ck;
for(int i = 0;i<m;i++){
int sz;
cin>>sz;
input(int,l,sz);
bitset<70>tp;
for(int j:l){
tp[j] = 1;
}
d.pb(tp);
}
// cout<<d.size()<<endl;
for(int i = 1;i<=n;i++)ck[i] = 1;
for(int i = 1;i<mx;i++){
int fst = (i&-i);
int idx = log2(fst);
mask[i] = (mask[i-fst]^d[idx]);
ans[i] = ans[i-fst];
ans[i].pb(idx+1);
}
vector<int>an;
for(int i = 0;i<n;i++)an.pb(n);
for(int i = 0;i<mx;i++){
if(mask[i] == ck){
sort(all(ans[i]));
if(ans[i].size() > an.size())continue;
if(an >= ans[i]){
an = ans[i];
}
}
}
cout<<an.size()<<endl;
// print(an);
for(int i = 0;i<an.size();i++){
cout<<an[i]<<" \n"[i == (int)(an.size()-1)];
}
}
signed main(){
ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE
cin.tie(0), cout.tie(0);
cout << fixed<<setprecision(9);
int t = 1;
// cin>>t;
for(int i = 1;i<=t;i++){
solve(i);
}
}
