102215H

#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> ii;
typedef long long ll;
#define sz(v) ((int)((v).size()))
#define all(v) (v).begin(),(v).end()

int solve(const int n, const function<int(int,int)>& ask) {
    int highestBit = 0;
    for (int i = 0; i <= 30; i++) {
        if (n & (1 << i)) {
            highestBit = i;
        }
    }

    vector<int> indices;
    for (int i = 1; i <= n; i++) {
        indices.push_back(i);
    }

    vector<int> values;
    for (int i = 0; i <= n; i++) {
        values.push_back(i);
    }

    for (int bit = 0; bit <= highestBit; bit++) {
        if (sz(values) == 1) break;

        vector<vector<int>> expected(2);
        for (int x : values) {
            expected[(x >> bit) & 1].push_back(x);
        }

        vector<vector<int>> have(2);
        for (int i : indices) {
            int val = ask(i, bit);
            have[val].push_back(i);
        }

        assert(
            (sz(have[0]) == sz(expected[0])) ^
            (sz(have[1]) == sz(expected[1]))
        );

        if (sz(have[0]) == sz(expected[0])) {
            values = expected[1];
            indices = have[1];
        } else {
            values = expected[0];
            indices = have[0];
        }

        //cerr << "indices: "; for (int x : indices) cerr << x << " "; cerr << endl;
        //cerr << "values: "; for (int x : values) cerr << x << " "; cerr << endl;

        assert(sz(indices) + 1 == sz(values));
    }

    assert(sz(indices) == 0);
    assert(sz(values) == 1);
    return values[0];
}

void stress() {
    ofstream log("log.txt");

    const int MAX_N = 1000;
    vector<int> a;
    for (int n = 1; n <= MAX_N; n++) {
        a.resize(n);
        for (int missing = 0; missing <= n; missing++) {
            int now = 0;
            for (int i = 0; i < n; i++) {
                if (now == missing) now++;
                a[i] = now++;
            }

            int questions = 0;
            function<int(int,int)> askEmulator = [&](const int index, const int bit) {
                assert(1 <= index && index <= n);
                questions++;
                int val = (a[index - 1] >> bit) & 1;
                //log << "  asking index = " << index << ", bit = " << bit << " -> val = " << val << endl;
                return val;
            };

            log << "===================" << endl;
            log << "n = " << n << ", missing = " << missing << endl;
            //log << "arr = "; for (int x : a) log << x << " "; log << endl;

            log.flush();
            const int res = solve(n, askEmulator);
            log << "res = " << res << ", questions = " << questions << endl;

            if (res != missing) {
                cerr << "ERROR: n = " << n << ", missing = " << missing << ", res = " << res << endl;
                throw;
            }
        }
        if (n % (MAX_N / 100) == 0) {
            cerr << "n = " << n << " is OK" << endl;
        }
    }
    cerr << "Stress completed" << endl;
}

int main() {
    //ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
    //cout.setf(ios::fixed); cout.precision(15);

    //stress(); return 0;

    int n;
    cin >> n;

    function<int(int,int)> askIO = [](const int index, const int bit) {
        cout << "? " << index << ' ' << bit << endl;
        int val;
        cin >> val;
        return val;
    };

    int res = solve(n, askIO);
    cout << "! " << res << endl;
}