#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ull=unsigned long long;
using P=pair<ll,ll>;
template<typename T>using minque=priority_queue<T,vector<T>,greater<T>>;
template<typename T>bool chmax(T &a,const T &b){return (a<b?(a=b,true):false);}
template<typename T>bool chmin(T &a,const T &b){return (a>b?(a=b,true):false);}
template<typename T1,typename T2>istream &operator>>(istream &is,pair<T1,T2>&p){is>>p.first>>p.second;return is;}
template<typename T1,typename T2,typename T3>istream &operator>>(istream &is,tuple<T1,T2,T3>&a){is>>std::get<0>(a)>>std::get<1>(a)>>std::get<2>(a);return is;}
template<typename T,size_t n>istream &operator>>(istream &is,array<T,n>&a){for(auto&i:a)is>>i;return is;}
template<typename T>istream &operator>>(istream &is,vector<T> &a){for(auto &i:a)is>>i;return is;}
template<typename T1,typename T2>void operator++(pair<T1,T2>&a,int n){a.first++,a.second++;}
template<typename T1,typename T2>void operator--(pair<T1,T2>&a,int n){a.first--,a.second--;}
template<typename T>void operator++(vector<T>&a,int n){for(auto &i:a)i++;}
template<typename T>void operator--(vector<T>&a,int n){for(auto &i:a)i--;}
#define overload3(_1,_2,_3,name,...) name
#define rep1(i,n) for(int i=0;i<(int)(n);i++)
#define rep2(i,l,r) for(int i=(int)(l);i<(int)(r);i++)
#define rep(...) overload3(__VA_ARGS__,rep2,rep1)(__VA_ARGS__)
#define reps(i,l,r) rep2(i,l,r)
#define all(x) x.begin(),x.end()
#define pcnt(x) __builtin_popcountll(x)
#define fin(x) return cout<<(x)<<'\n',static_cast<void>(0)
#define yn(x) cout<<((x)?"Yes\n":"No\n")
#define uniq(x) sort(all(x)),x.erase(unique(all(x)),x.end())
template<typename T>
inline int fkey(vector<T>&z,T key){return lower_bound(z.begin(),z.end(),key)-z.begin();}
ll myceil(ll a,ll b){return (a+b-1)/b;}
template<typename T,size_t n,size_t id=0>
auto vec(const int (&d)[n],const T &init=T()){
  if constexpr (id<n)return vector(d[id],vec<T,n,id+1>(d,init));
  else return init;
}
#ifdef LOCAL
#include<debug.h>
#define SWITCH(a,b) (a)
#else
#define debug(...) static_cast<void>(0)
#define debugg(...) static_cast<void>(0)
#define SWITCH(a,b) (b)
template<typename T1,typename T2>ostream &operator<<(ostream &os,const pair<T1,T2>&p){os<<p.first<<' '<<p.second;return os;}
#endif
struct Timer{
  clock_t start;
  Timer(){
    start=clock();
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout<<fixed<<setprecision(16);
  }
  inline double now(){return (double)(clock()-start)/1000;}
  #ifdef LOCAL
  ~Timer(){
    cerr<<"time:";
    cerr<<now();
    cerr<<"ms\n";
  }
  #endif
}timer;
void SOLVE();
int main(){
  int testcase=1;
  //cin>>testcase;
  for(int i=0;i<testcase;i++){
    SOLVE();
  }
}
void SOLVE(){
  int n;
  cin>>n;
  #ifdef LOCAL
  int m;
  cin>>m;
  vector<vector<bool>>edge(n,vector<bool>(n));
  rep(i,m){
    int u,v;
    cin>>u>>v;
    edge[u][v]=edge[v][u]=true;
  }
  #endif
  auto query=[&](vector<int>a,vector<int>b)->bool {
    if(a.empty()||b.empty())return false;
    cout<<"? ";
    cout<<a.size()<<' '<<b.size();
    rep(i,a.size())cout<<' '<<a[i]+1;
    rep(i,b.size())cout<<' '<<b[i]+1;
    cout<<endl;
    int res;
    #ifdef LOCAL
    res=0;
    rep(i,a.size())rep(j,b.size()){
      assert(a[i]!=b[j]);
      if(edge[a[i]][b[j]])res=1;
    }
    #else
    cin>>res;
    assert(res!=-1);
    #endif
    return res;
  };
  vector<pair<int,int>>ans;
  rep(i,n){
    vector<int>a={i};
    vector<int>b(n-i-1);
    iota(all(b),i+1);
    while(b.size()){
      if(!query(a,b))break;
      int ok=b.size(),ng=0;
      while(ok-ng>1){
        int mid=(ok+ng)/2;
        if(query(a,{b.begin(),b.begin()+mid}))ok=mid;
        else ng=mid;
      }
      ans.emplace_back(i,b[ok-1]);
      b.erase(b.begin(),b.begin()+ok);
    }
  }
  cout<<"! "<<ans.size()<<'\n';
  for(auto [u,v]:ans)cout<<u+1<<' '<<v+1<<'\n';
  cout.flush();
  #ifdef LOCAL
  sort(all(ans));
  rep(i,n)rep(j,i+1,n)assert(edge[i][j]==binary_search(all(ans),pair(i,j)));
  #endif
}