#include<bits/stdc++.h>
using namespace std;
using ll=long long;
ll c[26];
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n,m;
cin>>n>>m;
for(int i=0,q,x;i<m;++i){
cin>>q;
while(q--){
cin>>x;
c[i]|=(1ll<<(x-1));
}
}
ll g=0;
for(int i=0;i<n;++i)g|=(1ll<<i);
int ans=0,nw;
for(int j=0;j<m;++j)
ans|=(1<<j);
for(int msk=1;msk<(1<<m);++msk){
ll x=g;
nw=0;
for(int j=0;j<m;++j){
if(msk&(1<<j)){
x^=c[j];
nw|=(1<<j);
}
}
if(!x){
int pc1=__builtin_popcount(ans);
int pc2=__builtin_popcount(nw);
if(pc1<pc2)continue;
if(pc1>pc2)ans=nw;
else ans=min(ans,nw);
}
}
cout<<__builtin_popcount(ans)<<'\n';
for(int i=0;i<m;++i)
if(ans&(1<<i))cout<<i+1<<' ';
}
