#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
using ll = long long;

int f(int i, int j) {
    cout << "? " << i << ' ' << j << endl;
    int a;
    cin >> a;
    return a;
}

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

    int p[1024] = {};
    for (int i = 0; i < n; i++) {
        p[i + 512] = i + 1;
    }

    for (int i = 512 - 1; i > 0; i--) {
        if (p[i * 2 + 1] == 0) {
            p[i] = p[i * 2];
        } else {
            p[i] = f(p[i * 2], p[i * 2 + 1]);
        }
    }

    vector<int> q;
    int r = 0;
    for (int i = 1; i < 512;) {
        i = i * 2 + (p[i * 2] != p[i]);
        int t = p[i ^ 1];
        if (r == 0) {
            r = t;
        } else if (t != 0) {
            r = f(r, t);
        }
    }

    cout << "! " << r << endl;

    return 0;
}