#include <bits/stdc++.h>
using namespace std;

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

  auto get_winners = [](vector<int> a) {
    auto query = [](int x, int y) {
      ++x;
      ++y;
      if (!x || !y) return make_pair(x + y - 1, -1);
      cout << "? " << x << " " << y << endl;
      int w;
      cin >> w;
      return make_pair(w - 1, x + y - w - 1);
    };

    vector<vector<pair<int, int>>> winners(1);
    for (int u : a) winners[0].emplace_back(u, -1);
    for (int l = 0; 1 < winners[l].size(); ++l) {
      winners.resize(l + 2);
      for (int i = 0; i < winners[l].size(); i += 2) {
        if (i + 1 == winners[l].size()) {
          winners[l + 1].emplace_back(winners[l][i].first, -1);
        } else {
          winners[l + 1].emplace_back(query(winners[l][i].first, winners[l][i + 1].first));
        }
      }
    }

    return winners;
  };

  vector<int> a(N);
  iota(a.begin(), a.end(), 0);
  vector<vector<pair<int, int>>> winners = get_winners(a);

  vector<int> runners;
  for (int l = 0; l < winners.size(); ++l) {
    for (auto p : winners[l]) {
      if (p.first == winners.back()[0].first) {
        if (~p.second) {
          runners.push_back(p.second);
        }
      }
    }
  }

  vector<vector<pair<int, int>>> winners2 = get_winners(runners);
  cout << "! " << winners2.back()[0].first + 1 << endl;
  
  return 0;
}