#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define pii pair<int, int>
#define mp make_pair
#define fi first
#define se second 
#define deb(var) cerr << #var << '=' << var << "; "
#define int long long
namespace SUB {
	int n, tot;
	set<int> sub[2010], tmp; vector<pii> g;
	int main() {
		srand(time(0));
		tot = 1; sub[1].insert(1);
		for (int i = 2; i <= n; i++) {
			int ok = 0;
			for (int j = 1; j <= tot; j++) {
				cout << "? " << sub[j].size() + 1 << " " << i << " ";
				tmp = sub[j];
				for (set<int>::iterator it = tmp.begin(); it != tmp.end(); it++) cout << *it << " "; cout << endl;
				int u, v;
				cin >> u >> v;
				if (u != i) swap(u, v);
				if (u == -1 && v == -1) {
					if (!ok) ok = j;
					else if (rand() % 2) ok = j;
				}
				else {
					g.pb(mp(u, v));
					while (true) {
						tmp.erase(v);
						if (tmp.empty()) break;
						cout << "? " << tmp.size() + 1 << " " << i << " ";
						for (set<int>::iterator it = tmp.begin(); it != tmp.end(); it++) cout << *it << " "; cout << endl;
						cin >> u >> v;
						if (u != i) swap(u, v); 
						if (v != -1) {
							g.pb(mp(u, v));
						} else break;
					}
				}
			}
			if (ok) sub[ok].insert(i); else sub[++tot].insert(i);
		}
		cout << "! " << g.size() << endl;
		for (int i = 0; i < g.size(); i++) cout << g[i].fi << " " << g[i].se << endl;
		return 0;
	}
} 
int n, m, tot, ind[2010], lnd[2010], col[2010];
set<int> sub[2010], tmp; vector<int> g[2010]; vector<int> c; 
	set<pii> st; 
	int ord[2010], len;
void getsub(int n) {
	st.clear();
	for (int i = 1; i <= n; i++)
		st.insert(mp(ind[i], i));
	memcpy(lnd, ind, sizeof lnd);
	memset(col, 0, sizeof col); tot = 0;
	len = 0;
	while (st.size()) {
		set<pii>::iterator it = st.end(); it--;
		int u = (*it).se; ord[++len] = u; ind[u] = 0; st.erase(it);
		for (int j = 0; j < g[u].size(); j++) {
			if (ind[g[u][j]]) {
				st.erase(mp(ind[g[u][j]], g[u][j])); ind[g[u][j]]--; st.insert(mp(ind[g[u][j]], g[u][j]));
			}
		}
	}
	for (int i = len; i >= 1; i--) {
		int u = ord[i];
		c.clear();
		for (int j = 0; j < g[u].size(); j++) {
			if (col[g[u][j]]) c.pb(col[g[u][j]]);
		}
		sort(c.begin(), c.end());
		int lst = 0, now = 0;
		for (int i = 0; i < c.size(); i++)
			if (c[i] > lst + 1) {
				now = lst + 1; break;
			} else lst = c[i];
		col[u] = now;
		if (!now) col[u] = (c.size() ? c[c.size() - 1] + 1 : 1); tot = max(tot, col[u]);
	}
	memcpy(ind, lnd, sizeof lnd);
}
signed main() {
//	g[1].pb(2); g[1].pb(3);g[2].pb(1);g[3].pb(1);g[2].pb(5);g[5].pb(2);ind[1]=2;ind[2]=ind[3]=1;ind[2]++;ind[5]++; 
//	getsub(5);
//	for (int i=1;i<=5;i++)cout<<col[i]<<" ";
	cin >> n;
//	if ((n * n) <= 20000) {
//		SUB::n = n;
//		return SUB::main();
//	}
	tot = 1; sub[1].insert(1);
	for (int i = 2; i <= n; i++) {
		for (int j = 1; j <= tot; j++) {
			if (sub[j].empty()) continue;
			cout << "? " << sub[j].size() + 1 << " " << i << " ";
			tmp = sub[j];
			for (set<int>::iterator it = tmp.begin(); it != tmp.end(); it++) cout << *it << " "; cout << endl;
			int u, v;
			cin >> u >> v;
			if (u != i) swap(u, v);
			if (u == -1 && v == -1) {
			}
			else {
				g[u].pb(v), g[v].pb(u); m++; ind[u]++, ind[v]++;
				while (true) {
					tmp.erase(v);
					if (tmp.empty()) break;
					cout << "? " << tmp.size() + 1 << " " << i << " ";
					for (set<int>::iterator it = tmp.begin(); it != tmp.end(); it++) cout << *it << " "; cout << endl;
					cin >> u >> v;
					if (u != i) swap(u, v); 
					if (v != -1) {
						g[u].pb(v), g[v].pb(u); m++; ind[u]++, ind[v]++;
					} else break;
				}
			}
		}
		for (int i = 1; i <= tot; i++) sub[i].clear();
		getsub(i);
		for (int j = 1; j <= i; j++) sub[col[j]].insert(j);
	}
	cout << "! " << m << endl;
	for (int i = 1; i <= n; i++) {
		for (int j = 0; j < g[i].size(); j++)
			if (g[i][j] > i) cout << i << " " << g[i][j] << endl;
	}
	return 0;
}