#include<bits/stdc++.h>
using namespace std;
using ll=long long;
int n,m;
vector<int>ans;
vector<int>sp[27],koji[66],nemaju[66];
ll bsp[26],b;
bool losi[(1<<25)],imao[(1<<25)];
bool bolje(const bitset<25>a,const bitset<25>b){
int c1=a.count();
int c2=b.count();
if(c1>c2)return 0;
if(c1<c2)return 1;
for(int i=0;i<a.size();++i){
if(a[i]>b[i])return 1;
if(a[i]<b[i])return 0;
}
return 0;
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cin>>n>>m;
bitset<66>bb;
for(int i=0,q,x;i<m;++i){
cin>>q;
bb=0;
while(q--){
cin>>x;
sp[i].push_back(x);
koji[x].push_back(i);
bsp[i]+=(1<<x);
bb[x]=1;
}
for(int j=1;j<=n;++j){
if(!bb[j])nemaju[j].push_back(i);
}
}
for(int x=1;x<=n;++x){
int msk=0;
for(int i:koji[x])
msk^=(1<<i);
if(imao[msk])continue;
imao[msk]=1;
for(int s=msk;s;s=(s-1)&msk)
if(__builtin_popcount(s)&1^1)losi[s]=1;
}
fill(imao,imao+(1<<25),0);
for(int x=1;x<=n;++x){
int msk=0;
for(int i:nemaju[x])
msk^=(1<<i);
if(imao[msk])continue;
imao[msk]=1;
for(int s=msk;s;s=(s-1)&msk)losi[s]=1;
}
bitset<25>ans,nw;
for(int i=0;i<m;++i)
ans[i]=1;
for(int msk=1;msk<(1<<m);++msk){
if(losi[msk])continue;
b=0;
for(int i=0;i<m;++i)
if(msk&(1<<i))b^=bsp[i];
if(__builtin_popcountll(b)!=n)continue;
nw=0;
for(int j=0;j<m;++j)
nw[j]=((msk&(1<<j))!=0);
if(bolje(nw,ans))ans=nw;
}
cout<<ans.count()<<'\n';
for(int i=0;i<m;++i)
if(ans[i])cout<<i+1<<' ';
}
