#include <bits/stdc++.h>

template <typename T>
void rd(T& x){
	x = 0; char c = getchar(); int f = 1;
	while(!isdigit(c)) f = c == '-' ? -1 : 1, c = getchar();
	while(isdigit(c)) x = x * 10 + c - '0', c = getchar();
	x *= f;
}
template <typename T, typename... Args>
void rd(T& x, Args&... args){rd(x); rd(args...);}
template <typename T>
void wt(T x, char ed){
	if(x < 0) putchar('-'), x = -x;
	static short st[20], tp;
	do st[++tp] = x % 10, x /= 10; while(x);
	while(tp) putchar(st[tp--] + '0');
	putchar(ed);
	if(ed == '\n') fflush(stdout);
}

const int N = 2006;

int n, col[N];
std::vector <int> nds[N], G[N];
std::vector <std::pair <int, int>> edges;

bool ban[N], vis[N];

void adde(int u, int v){
	edges.push_back({u, v});
	G[u].push_back(v), G[v].push_back(u);
}

bool qry(std::vector <int> V){
	putchar('?'), putchar(' ');
	int siz = V.size();
	wt(siz, ' ');
	for(int i = 0; i < siz; ++i) wt(V[i], " \n"[i == siz - 1]);
	int u, v; rd(u, v);
	if(u == -1) return 0;
	else{
		if(u > v) std::swap(u, v);
		adde(u, v), ban[u] = 1;
		return 1;
	}
}

void answer(){
	putchar('!'), putchar(' '), wt(edges.size(), '\n');
	for(auto P : edges) wt(P.first, ' '), wt(P.second, '\n');
}

int p[N], deg[N];
void recolour(int n){
	for(int i = 1; i <= n; ++i) p[i] = i, deg[i] = G[i].size(), col[i] = 0, nds[i].clear();
	std::sort(p + 1, p + n + 1, [&](int i, int j){return deg[i] > deg[j];});
	for(int i = 1, x; i <= n; ++i){
		x = p[i];
		for(auto y : G[x]) vis[col[y]] = 1;
		int mex = 1;
		while(vis[mex]) ++mex;
		col[x] = mex, nds[mex].push_back(x);
		for(auto y : G[x]) vis[col[y]] = 0;
	}
}

int main(){
	rd(n);
	col[1] = 1, nds[1].push_back(1);
	for(int i = 2; i <= n; ++i){
		memset(ban, 0, sizeof ban);
		for(int j = 1; j <= n; ++j){
			if(!nds[j].size()) continue;
			while(1){
				std::vector <int> nxt;
				for(auto p : nds[j]) if(!ban[p]) nxt.push_back(p);
				nxt.push_back(i);
				if(nxt.size() == 1) break;
				bool fl = qry(nxt);
				if(!fl) break;
			}
		}
		recolour(i);
	}
	answer();
	return 0; 
}