/*
#include<bits/stdc++.h>
using namespace std;
#define eb emplace_back
#define Debug(...) fprintf(stderr,__VA_ARGS__)
template<typename T>
void read(T &x){
	scanf("%d",&x);
}
template<typename T,typename... Args>
void read(T &x,Args &...args){read(x),read(args...);}
const int N=2e3+7;
int n,K=0,ban[N],tim;
vector<int>s[N];
vector<pair<int,int> >e;
int main(){
	read(n);
	auto ask=[&](int u,int siz,vector<int>&S){
		tim++;assert(tim!=6001);
		printf("? %d ",(int)siz+1);
		printf("%d ",u);
		for(auto v:S)if(ban[v]!=ban[0])printf("%d ",v);
		printf("\n");
		fflush(stdout);
	};
	for(int i=ban[0]=1;i<=n;i++,ban[0]++){
		if(i==1){s[++K].eb(1);continue;}
		else{
			int pos=0,flg=0;
			for(int j=1,p,q;j<=K;j++){
				flg=0;ask(i,s[j].size(),s[j]);read(p,q);
				while(p!=-1){
					if(p==i)swap(p,q);
					ban[p]=ban[0];e.eb(make_pair(p,q));
					flg++;if(flg==(int)s[j].size())break;
					ask(i,s[j].size()-flg,s[j]);read(p,q);
				}
				if(!flg&&!pos)pos=j;
			}
			if(!pos)pos=++K;
			s[pos].eb(i);
		}
	}
	printf("! %d\n",(int)e.size());
	for(auto [u,v]:e)printf("%d %d\n",u,v);
	fflush(stdout);
	return 0;
}
*/
#include<bits/stdc++.h>
#define pii pair<int,int>
#define fi first
#define se second
#define mk make_pair
#define pb push_back 
using namespace std;
const int N=2e3+100;
int k,n;
int tag[N];
vector<int>g[N];
vector<int>col[N];
void rebuild(int n)
{
	static int deg[N],vis[N],num[N],c[N];
	priority_queue<pii,vector<pii>,greater<pii> >q;stack<int>st;
	memset(deg,0,sizeof(deg));memset(vis,0,sizeof(vis));memset(c,0,sizeof(c));
	k=0;
	for(int i=1;i<=n;i++)q.push(mk(deg[i]=g[i].size(),i));
	while(!q.empty())
	{
		int x=q.top().se;q.pop();
		if(vis[x])continue;vis[x]=1;
		k=max(k,deg[x]+1);st.push(x);
		for(auto y:g[x])if(!vis[y])q.push(mk(--deg[y],y));
	}
	for(int i=1;i<=k;i++)col[i].clear();
	while(!st.empty())
	{
		int x=st.top();st.pop();vis[x]=0;
		memset(num,0,sizeof(int)*(k+10));
		for(auto y:g[x])if(!vis[y])num[c[y]]++;
		for(int i=1;i<=k;i++)if(!num[i]){col[c[x]=i].push_back(x);break;}
	}
}
int main()
{
	scanf("%d",&n);int m=0;
	for(int i=1;i<=n;i++)
	{
		memset(tag,0,sizeof(tag));
		for(int j=1,cnt=0;j<=k;j++,cnt=0)
			while(cnt<col[j].size())
			{
				printf("? %d ",col[j].size()-cnt+1);for(auto y:col[j])if(!tag[y])printf("%d ",y);printf("%d\n",i);
				int x,y;fflush(stdout);scanf("%d%d",&x,&y);
				if(x<0&&y<0)break;cnt++;m++;
				tag[min(x,y)]=1;g[x].push_back(y);g[y].push_back(x);
			}
		rebuild(i);
	}
	printf("! %d\n",m);
	for(int i=1;i<=n;i++)
	{
		sort(g[i].begin(),g[i].end());
		for(auto y:g[i])if(i<y)printf("%d %d\n",i,y);
	}
	return 0;
}