#include <stdio.h>

int main(void) {
	int i, ask = (1 << 30), ans0, ans1 = -1, y;
	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));
		printf("? %d\n", ask - (2 * i + 1) ); fflush(stdout);
		scanf("%d", &ans1);
		if(ans1 == 0 || i == 29) {
			y = ask + ((i == 29) ? ans1 : 0);
			break;
		}
	}
	printf("! %d\n", y); fflush(stdout);
	return 0;
}