#include<bits/stdc++.h>
using namespace std;
namespace my_std{
	#define ll long long
	#define bl bool
	ll my_pow(ll a,ll b,ll mod){
		ll res=1;
		if(!b) return 1;
		while(b){
			if(b&1) res=(res*a)%mod;
			a=(a*a)%mod;
			b>>=1;
		}
		return res;
	}
	ll qpow(ll a,ll b){
		ll res=1;
		if(!b) return 1;
		while(b){
			if(b&1) res*=a;
			a*=a;
			b>>=1;
		}
		return res;
	}
	#define db double
	#define pf printf
	#define pc putchar
	#define fr(i,x,y) for(register ll i=(x);i<=(y);i++)
	#define pfr(i,x,y) for(register ll i=(x);i>=(y);i--)
	#define go(u) for(ll i=head[u];i;i=e[i].nxt)
	#define enter pc('\n')
	#define space pc(' ')
	#define fir first
	#define sec second
	#define MP make_pair
	#define il inline
	#define inf 8e18
	#define random(x) rand()*rand()%(x)
	#define inv(a,mod) my_pow((a),(mod-2),(mod))
	il ll read(){
		ll sum=0,f=1;
		char ch=0;
		while(!isdigit(ch)){
			if(ch=='-') f=-1;
			ch=getchar();
		}
		while(isdigit(ch)){
			sum=sum*10+(ch^48);
			ch=getchar();
		}
		return sum*f;
	}
	il void write(ll x){
		if(x<0){
			x=-x;
			pc('-');
		}
		if(x>9) write(x/10);
		pc(x%10+'0');
	}
	il void writeln(ll x){
		write(x);
		enter;
	}
	il void writesp(ll x){
		write(x);
		space;
	}
}
using namespace my_std;
#define fl fflush(stdout)
vector<ll> vec[2020],qry;
vector<pair<ll,ll> > ans;
ll n,k=0;
bl ck[2020],pd[2020];
void query(){
	pf("? %lld ",qry.size());
	fr(i,0,(ll)qry.size()-1) writesp(qry[i]);
	enter;
	fl;
}
int main(){
	n=read();
	fr(i,1,n){
		fr(j,1,k) ck[j]=0;
		fr(j,1,k){
			fr(l,0,(ll)vec[j].size()-1) pd[vec[j][l]]=0;
			while(1){
				qry.clear();
				fr(l,0,(ll)vec[j].size()-1) if(!pd[vec[j][l]]) qry.push_back(vec[j][l]);
				if(qry.empty()) break;
				qry.push_back(i);
				query();
				ll u=read(),v=read();
				if(u==-1) break;
				ck[j]=1;
				if(v==i) pd[u]=1;
				else pd[v]=1;
				ans.push_back(MP(u,v));
			}
		}
		bl ckk=0;
		fr(j,1,k){
			if(!ck[j]){
				vec[j].push_back(i);
				ckk=1;
				break;
			}
		}
		if(!ckk){
			k++;
			vec[k].push_back(i);
		}
	}
	pf("! %lld\n",(ll)ans.size());
	fr(i,0,(ll)ans.size()-1) pf("%lld %lld\n",ans[i].fir,ans[i].sec);
	fl;
}