#include<bits/stdc++.h>
using namespace std;
#define rep(i,x,y) for (int i=(x);i<=(y);i++)
#define drep(i,y,x) for (int i=(y);i>=(x);i--)
#define pii pair<int,int>
#define fir first
#define sec second
#define MP make_pair
template<typename T> bool chkmin(T &x,T y){return x>y?x=y,1:0;}
template<typename T> bool chkmax(T &x,T y){return x<y?x=y,1:0;}
void file() {
    #ifdef zqj
    freopen("a.in","r",stdin);
    #endif
}
typedef long long ll;
#define sz 4444

ll seed=time(0)+(size_t)(new char);

int n;
vector<int>V[sz];
int e[sz][sz];

void init() {
    #ifdef zqj
    n=4000;
    mt19937 rng(seed);
    int m=10000;
    rep(_,1,m) {
        int x=rng()%n+1,y=rng()%n+1;
        ++e[x][y];
        if (y!=x) ++e[y][x];
    }
    #endif
}

vector<int> ask(vector<int>v) {
    #ifdef zqj
    static int tot=0;
    tot+=v.size();
    assert(tot<=176000);
    // printf("? %d ",(int)v.size());
    // for (auto x:v) printf("%d ",x);
    // puts("");
    vector<int>S,res;
    for (auto x:v) {
        int cc=0;
        for (auto y:S) cc+=e[y][x];
        if (!cc) S.push_back(x);
        res.push_back(cc);
    }
    // for (auto x:res) printf("%d ",x);
    // puts("");
    return res;
    #else
    printf("? %d ",(int)v.size());
    for (auto x:v) printf("%d ",x);
    puts("");
    fflush(stdout);
    vector<int>res(v.size());
    rep(i,0,(int)v.size()-1) cin>>res[i];
    return res;
    #endif
}

vector<int> concat(const vector<int>&L,const vector<int>&R) {
    vector<int>res=L;
    res.insert(res.end(),R.begin(),R.end());
    return res;
}

void solve(vector<int>L,vector<int>_R,vector<int>_deg) {
    int m=L.size();
    if (!m) return;
    vector<int>R,deg;
    rep(i,0,(int)_R.size()-1) if (_deg[i]) R.push_back(_R[i]),deg.push_back(_deg[i]);
    if (m==1) {
        rep(i,0,(int)R.size()-1) rep(_,1,deg[i]) V[R[i]].push_back(L[0]),V[L[0]].push_back(R[i]);
        return;
    }
    vector<int>L1(L.begin(),L.begin()+m/2),L2(L.begin()+m/2,L.end());
    auto res=ask(concat(L1,R));
    map<int,int>rnk; int cc=0;
    for (auto x:R) ++cc,rnk[x]=cc;
    vector<int>deg1,deg2,R1,R2;
    rep(i,0,(int)R.size()-1) {
        int d=res[i+L1.size()];
        for (auto v:V[R[i]]) if (rnk.count(v)&&!res[rnk[v]-1+L1.size()]&&rnk[v]<rnk[R[i]]) --d;
        if (d) deg1.push_back(d),R1.push_back(R[i]);
        if (d!=deg[i]) deg2.push_back(deg[i]-d),R2.push_back(R[i]);
    }
    solve(L1,R1,deg1),solve(L2,R2,deg2);
}

void solve(vector<int>id) {
    vector<int>ww=ask(id);
    vector<int>L,R;
    rep(i,0,(int)id.size()-1) if (!ww[i]) L.push_back(id[i]); else R.push_back(id[i]);
    if (!R.size()) {
        // for (auto x:L) {
        //     auto res=ask({x,x});
        //     rep(_,1,res[1]) V[x].push_back(x);
        // }
        return;
    }
    solve(R);
    vector<int>vv=concat(L,R);
    map<int,int>rnk; int cc=0;
    for (auto x:R) ++cc,rnk[x]=cc;
    auto res=ask(vv);
    vector<int>deg(R.size());
    rep(i,0,(int)R.size()-1) {
        int d=res[i+L.size()];
        for (auto v:V[R[i]]) if (rnk.count(v)&&!res[rnk[v]-1+L.size()]&&rnk[v]<rnk[R[i]]) --d;
        deg[i]=d;
    }
    solve(L,R,deg);
    // rep(i,0,(int)L.size()-1) rep(_,1,res[i+L.size()]) V[L[i]].push_back(L[i]);
}

int main() {
    srand(seed);
    cerr<<seed<<'\n';
    init();
    #ifndef zqj
    cin>>n;
    #endif
    vector<int>id;
    rep(i,1,n) id.push_back(i);
    random_shuffle(id.begin(),id.end());
    solve(id);
    rep(i,1,n) {
        vector<int>v({i,i});
        auto res=ask(v);
        rep(_,1,res[1]) V[i].push_back(i);
    }
    #ifdef zqj
    // rep(i,1,n) {
    //     rep(j,1,n) cerr<<e[i][j]<<' ';
    //     cerr<<'\n';
    // }
    // int m=0;
    // rep(i,1,n) for (auto v:V[i]) if (v<=i) ++m;
    // cerr<<m<<'\n';
    // rep(i,1,n) for (auto v:V[i]) if (v<=i) cerr<<i<<' '<<v<<'\n';
    rep(i,1,n) for (auto v:V[i]) if (v<=i) {
        --e[i][v];
        if (v!=i) --e[v][i];
    }
    rep(i,1,n) rep(j,1,n) assert(!e[i][j]);
    puts("OK");
    #else
    int m=0;
    rep(i,1,n) for (auto v:V[i]) if (v<=i) ++m;
    printf("! %d ",m);
    rep(i,1,n) for (auto v:V[i]) if (v<=i) printf("%d %d ",i,v);
    fflush(stdout);
    #endif
    return 0;
}