#include <iostream>
using namespace std;

int main()
{
	int n;
	cin >> n;
	cout << "? " << n / 2 << endl;
	int s;
	cin >> s;
	if(s == n / 2 || s == 0){
		cout << "! " << 2 << " " << n - 1 << endl;
		return 0;
	}
	if(s * 2 == n){
		cout << "! " << 1 << " " << n << endl;
		return 0;
	}
	bool f = true;
	if(s * 2 < n) f = false;
	int left = 0, right = n;
	while(right - left > 1){
		int mid = (right + left) / 2;
		cout << mid << endl;
		int s;
		cin >> s;
		if(s * 2 == mid){
			cout << "! " << mid + 1 << " " << n * 2 << endl;
			return 0;
		}
		if((s * 2 < n) == f) left = mid;
		else right = mid;
	}
}