#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> BI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(1); 
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=4010;
int n,ind[N],sl[N];
vector<PII> nd[N],E;
VI xs[N];
int wt;
//#define LOCAL

#ifdef LOCAL
int m;
VI e[N];
bool mark[N];
vector<PII> es;
#endif
VI query(VI x) {
	wt+=SZ(x);
	printf("? %d",SZ(x));
	for (auto u:x) printf(" %d",u); puts("");
	fflush(stdout);
	VI cnt(SZ(x),0);
#ifdef LOCAL
	rep(i,0,SZ(x)) {
		int u=x[i];
		for (auto v:e[u]) if (mark[v]) cnt[i]++;
		if (cnt[i]==0) mark[u]=1;
	}
	rep(i,0,SZ(x)) mark[x[i]]=0;
	printf("answer: ");
	rep(i,0,SZ(x)) printf("%d ",cnt[i]); puts("");
#else
	rep(i,0,SZ(x)) {
		scanf("%d",&cnt[i]);
	}
#endif
	return cnt;
}

int tmpd[N];
vector<int> eg[N];
int main() {
	scanf("%d",&n);
#ifdef LOCAL
	scanf("%d",&m);
	rep(i,0,m) {
		int u=rnd(n)+1,v=rnd(n)+1;
		printf("E %d %d\n",u,v);
		es.pb(mp(u,v));
		if (u!=v) e[u].pb(v),e[v].pb(u);
		else e[u].pb(u);
	}
#endif
	rep(i,1,n+1) {
		auto d=query(VI{i,i});
		sl[i]=d[1];
		rep(j,0,sl[i]) E.pb(mp(i,i));
	}
	VI ord;
	rep(i,1,n+1) ord.pb(i);
	auto adde=[&](int u,int v) {
		eg[u].pb(v);
		eg[v].pb(u);
		E.pb(mp(u,v));
	};
	function<void(VI,vector<PII>)> solvebip=[&](VI l,vector<PII> r) {
		if (r.empty()) return;
		if (SZ(l)==1) {
			for (auto [v,deg]:r) {
				rep(j,0,deg) adde(l[0],v);
			}
		} else {
			int md=SZ(l)/2;
			VI l0(l.begin(),l.begin()+md),l1(l.begin()+md,l.end());
			vector<PII> r0,r1;
			VI qr=l0;
			for (auto [x,deg]:r) qr.pb(x);
			auto d=query(qr);
			set<int> mk;
			for (auto [v,deg]:r) tmpd[v]=deg;
			rep(i,SZ(l0),SZ(qr)) {
				int u=qr[i];
				int v=d[i];
				if (v==0) mk.insert(u);
				for (auto w:eg[u]) if (mk.count(w)) --v;
				if (v>0) r0.pb(mp(u,v));
				if (tmpd[u]-v>0) r1.pb(mp(u,tmpd[u]-v));
			}
			solvebip(l0,r0);
			solvebip(l1,r1);
		}
	};
	function<void(VI)> solve=[&](VI ord) {
		shuffle(all(ord),mrand);
		if (SZ(ord)<=1) return;
		auto d=query(ord);
		VI s,ns;
		rep(i,0,SZ(ord)) {
			if (d[i]==0) s.pb(ord[i]); else ns.pb(ord[i]);
		}
		solve(ns);
		VI qr=s; qr.insert(qr.end(),all(ns));
		d=query(qr);
		vector<PII> r;
		rep(i,SZ(s),SZ(qr)) {
			assert(d[i]>0);
			r.pb(mp(qr[i],d[i]));
		}
		solvebip(s,r);
	};
	solve(ord);
	printf("! %d",SZ(E));
	for (auto [x,y]:E) printf(" %d %d",x,y);
	puts("");
	fflush(stdout);
#ifdef LOCAL
	for (auto &[x,y]:E) if (x>y) swap(x,y); sort(all(E));
	for (auto &[x,y]:es) if (x>y) swap(x,y); sort(all(es));
	assert(E==es);
	printf("total : %d\n",wt);
#endif
}