//Author: Kevin
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb emplace_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) reverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
int E[2002][2002];
int ok[2002],deg[2002],color[2002];
vector<int> G[2002];
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		memset(ok,0,sizeof(ok));
		for(int j=i+1;j<=n;j++)
			if(!E[i][j])
				ok[j]=1;
		while(true)
		{
			vector<int> vec;
			for(int j=i+1;j<=n;j++)
				if(ok[j])
					vec.pb(j);
			if(!sz(vec)) break;
			memset(deg,0,sizeof(deg));
			memset(color,-1,sizeof(color));
			for(int j=i+1;j<=n;j++) if(ok[j])
				for(auto k:G[j])
					if(ok[k])
						deg[k]++;
			priority_queue<pii,vector<pii>,greater<pii>> pq;
			for(int j=i+1;j<=n;j++)
				if(ok[j])
					pq.emplace(deg[j],j);
			vector<int> order;
			while(!pq.empty())
			{
				int x=pq.top().second;
				int cnt=pq.top().first;
				pq.pop();
				if(deg[x]==-1) continue;
				order.pb(x);
				deg[x]=-1;
				for(auto y:G[x])
					if(ok[y]&&deg[y]>=0)
					{
						deg[y]--;
						pq.emplace(deg[y],y);
					}
			}
			rev(order);
			int mx=0;
			for(auto u:order)
			{
				set<int> st;
				for(auto v:G[u])
					if(ok[v])
						st.insert(color[v]);
				color[u]=0;
				while(st.count(color[u])) color[u]++;
				mx=max(mx,color[u]);
			}
			vector<int> vq;
			vq.pb(i);
			for(auto u:order)
				if(!color[u])
					vq.pb(u);
			cout<<"? "<<sz(vq);
			for(auto x:vq)
				cout<<" "<<x;
			cout<<endl;
			int a,b;
			cin>>a>>b;
			if(a==-1)
			{
				for(auto u:order)
					if(!color[u])
						ok[u]=0;
				continue;
			}
			if(b==i) swap(a,b);
			if(a!=i)
			{
				E[a][b]=E[b][a]=1;
				G[a].pb(b);
				G[b].pb(a);
				continue;
			}
			E[a][b]=E[b][a]=1;
			G[a].pb(b);
			G[b].pb(a);
			ok[b]=0;
		}
	}
	vector<pii> ans;
	for(int i=1;i<=n;i++)
		for(int j=i+1;j<=n;j++)
			if(E[i][j])
				ans.pb(i,j);
	cout<<"! "<<sz(ans)<<endl;
	for(auto pr:ans)
		cout<<pr.first<<" "<<pr.second<<endl;
	return 0;
}