/// @author Camillus <3
#ifndef LOCAL
#define debug(...) 42
#endif
#include "bits/stdc++.h"
using namespace std;

int query(int x, int y) {
    cout << "? " << x << " " << y << endl;
    int result;
    cin >> result;
    return result;
}

int answer(int s) {
    cout << "! " << s << endl;
    exit(0);
}


signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int R, C, L;
    cin >> R >> C >> L;

    int x, y;

    {
        int l = 0, r = C;

        while (r - l > 2) {
            int m1 = l + (r - l) / 3;
            int m2 = r - (r - l) / 3;

            if (query(0, m1) < query(0, m2)) {
                r = m2;
            } else {
                l = m1;
            }
        }

        y = l;
        for (int i = l + 1; i <= r; i++) {
            if (query(0, i) < query(0, y)) {
                y = i;
            }
        }
    }

    {
        int l = 0, r = R;

        while (r - l > 2) {
            int m1 = l + (r - l) / 3;
            int m2 = r - (r - l) / 3;

            if (query(m1, 0) < query(m2, 0)) {
                r = m2;
            } else {
                l = m1;
            }
        }

        x = l;
        for (int i = l + 1; i <= r; i++) {
            if (query(i, 0) < query(x, 0)) {
                x = i;
            }
        }
    }

    answer(query(x, y));
    return 0;
}