#include <bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1e9 + 7;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}


int ask(int x, int y) {
  if(x == -1) return y;
  if(y == -1) return x;
  cout << "? " << x << " " << y << endl;
  int k;
  cin >> k;
  return k;
}


int main() {
  int N;
  cin >> N;

  function< pair< int, int >(int, int) > rec = [&](int l, int r) {
    if(l + 1 == r) {
      return make_pair(l, -1);
    } else {
      int md = (l + r) / 2;
      auto L = rec(l, md);
      auto R = rec(md, r);
      if(L.second == -1) swap(L, R);

      if(ask(R.first, L.first) == R.first) {
        L.second = L.first;
        L.first = R.first;
        if(ask(R.second, L.second) == R.second) {
          L.second = R.second;
        }
      } else if(ask(R.first, L.second) == R.first) {
        L.second = R.first;
      }
      return L;
    }
  };
  auto ret = rec(1, N + 1).second;
  cout << "! " << ret << endl;
}