#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

inline int Query(const set<int>& st) {
  if (st.size() == 1) return 0;
  cout << "? " << st.size() << '\n';
  for (int x : st) cout << x + 1 << ' ';
  cout << endl;
  int x;
  cin >> x;
  return x;
}

int main() {
  int n;
  cin >> n;
  set<int> st;
  rep(i, n) st.insert(i);
  rep(i, n) {
    st.erase(i);
    int x = Query(st);
    if (x == 0) st.insert(i);
  }
  cout << "! " << st.size() << '\n';
  for (int x : st) cout << x + 1 << ' ';
  cout << endl;
  return 0;
}