#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
using namespace std;
#define fi first
#define sc second
#define mkp make_pair
#define pii pair<int,int>
typedef long long ll;
const int N=2005,oo=1e9;
inline int read() {
    int x=0,flag=0;char ch=getchar();
    while(ch<'0'||ch>'9') {flag|=(ch=='-');ch=getchar();}
    while('0'<=ch&&ch<='9') {x=(x<<3)+(x<<1)+ch-'0';ch=getchar();}
    return flag?-x:x;
}

int n,m; bool vis[N],Vis[N],f[N][N];
inline pii query(vector<int>S) {
    printf("? %d ",S.size());
    for(int&V:S) printf("%d ",V);
    printf("\n");
    fflush(stdout);
    return mkp(read(),read());
}
int main() {
    n=read(); pii qwq;
    for(int i=1;i<=n;++i) {
        if(vis[i]) continue;
        vis[i]=1; vector<int>now={i},Now;
        for(int j=1;j<=n;++j) {
            if(vis[j]) continue;
            Now=now; Now.push_back(j);
            qwq=query(Now);
            if(qwq.fi==-1&&qwq.sc==-1) {
                vis[j]=1;
                now.push_back(j);
            } else f[qwq.fi][qwq.sc]=f[qwq.sc][qwq.fi]=1,++m;
        }
        bool flag=1;
        while(flag) {
            flag=0;
            for(int j=1;j<=n;++j) {
                if(vis[j]||Vis[j]) continue;
                Now.clear();
                for(int&V:now) if(!f[j][V]) Now.push_back(V);
                if(Now.empty()) {Vis[j]=1;continue;}
                Now.push_back(j);
                qwq=query(Now);
                if(qwq.fi==-1&&qwq.sc==-1) Vis[j]=1;
                else {
                    flag=1;
                    f[qwq.fi][qwq.sc]=f[qwq.sc][qwq.fi]=1,++m;
                }
            }
        }
        for(int j=1;j<=n;++j) Vis[j]=0;
    }
    printf("! %d\n",m);
    for(int i=1;i<=n;++i)
        for(int j=i+1;j<=n;++j)
            if(f[i][j]) printf("%d %d\n",i,j);
    return 0;
}