#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cctype>
#include<cstdlib>
#include<algorithm>
#include<bitset>
#include<vector>
#include<list>
#include<deque>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<sstream>
#include<fstream>
#include<iomanip>
#include<ctime>
#include<complex>
#include<functional>
#include<climits>
#include<cassert>
#include<iterator>
#include<unordered_map>
#include<stdint.h>
using namespace std;

int main(void) {
	int i, ask = (1 << 30), ans0, ans1 = -1, y=0;
	for (i = 0; i < 30; i++) {
		printf("? %d\n", 1); fflush(stdout);
		scanf("%d", &ans0);
		if (ans0 != 1) {
			y = 2 * i + (ans0 == 0);
			break;
		}

		ask += ans1 * (1 << (29 - i));
		int k = ask - (k*i + 1);
		k = 0;
		printf("? %d\n", ask - (2 * i + 1)); fflush(stdout);
		scanf("%d", &ans1);
		if (ans1 == 0) {
			y = ask;
			break;
		}
	}
	printf("! %d\n", y); fflush(stdout);
	return 0;
}