#include<bits/stdc++.h>
using namespace std;
int n,m;
vector<int>ans;
vector<int>sp[27],koji[66];
bitset<66>bsp[26];
bool losi[(1<<25)],imao[(1<<25)];
bool bolje(const string&a,const string&b){
int c1=count(a.begin(),a.end(),'1');
int c2=count(b.begin(),b.end(),'1');
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;
for(int i=0,q,x;i<m;++i){
cin>>q;
while(q--){
cin>>x;
sp[i].push_back(x);
koji[x].push_back(i);
bsp[i][x]=1;
}
}
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;
}
string ans;
for(int i=0;i<m;++i)
ans.push_back('1');
for(int msk=1;msk<=(1<<m);++msk){
if(losi[msk])continue;
bitset<66>b;
for(int i=0;i<m;++i)
if(msk&(1<<i))b^=bsp[i];
if(b.count()!=n)continue;
string s;
for(int j=0;j<m;++j)
s.push_back('0'+((msk&(1<<j))!=0));
if(bolje(s,ans))ans=s;
}
cout<<count(ans.begin(),ans.end(),'1')<<'\n';
for(int i=0;i<m;++i)
if(ans[i]=='1')cout<<i+1<<' ';
}
