// #ifdef __AVX2__
// #pragma GCC target "avx2"
// #endif
// #pragma GCC optimize "O3"
// #pragma GCC optimize "unroll-loops"
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
using namespace std;
#define int unsigned long long
#define elif else if
#define all(l) begin(l),end(l)
#define rall(l) rbegin(l),rend(l)
#define append push_back
#define print(l) for(auto i:l) cout<<i<<' '; cout<<endl;
#define pprint(a,b) cout<<a<<' '<<b<<endl;
#define inp(l) for(auto &i:l) cin>>i;
// #define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define pai make_pair
#define endl "\n"
#define pii pair<int,int>
#define fi first
#define se second
#define vec vector
// const int mod=998244353;
const int mod1=998244353;
const int mod=1e9+7;
const int N=2e5+5;
int iter=1,itera=1;
void solve(){
int n,m;
cin>>n>>m;
vec<int>a;
for(int i=0;i<m;i++){
int s;
cin>>s;
vec<int>b(s);
inp(b);
int x=0;
for(auto i:b){
int tem=1;
tem=tem<<(i-1);
x+=tem;
}
a.append(x);
}
int si=(1<<m);
vec<int>dp(si,0);
vec<int>val(si,0);
vec<bool>vis(si,0);
vis[0]=1;
int ans=(1ll<<30)-1;
int tem=1;
tem=(tem<<n)-1;
vec<int>pos={0};
for(int i=0;i<m;i++){
int v=(1ll<<i);
for(auto x:pos){
int g=x|v;
dp[g]=dp[x]^a[i];
vis[g]=1;
if(dp[g]==tem){
int cur1=__builtin_popcountll(g);
int cur=__builtin_popcountll(ans);
if(cur1<cur) ans=g;
elif(cur1==cur){
for(int i=0;i<m;i++){
bool g1=(g>>i)&1;
bool ans1=(ans>>i)&1;
if(g1==ans1) continue;
if(g1) ans=g;
break;
}
}
}
}
for(int i=0;i<v;i++) pos.append(pos[i]|v);
}
cout<<__builtin_popcountll(ans)<<endl;
for(int i=1;i<=m;i++){
if(ans&1) cout<<i<<' ';
ans>>=1;
}
}
signed main(){
// freopen("","r",stdin);
// freopen("","w",stdout);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cout<<fixed<<setprecision(20);
// cin>>itera;
for(iter=1;iter<=itera;iter++) solve();
}
