package yukicoder253;
import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		System.out.println("?100");
		System.err.println(1000000000);
		int a=sc.nextInt();
		int count=0;
		if(a==-1){
			for(int i=0;i<100;i++){
				System.out.println("?0");
				count++;
				int b=sc.nextInt();
				if(b==0){
					System.out.println("!"+count);
					sc.close();
					System.exit(0);
				}
			}
		}else if(a==1){
			int upper=(int)Math.pow(10,9);
			int low=101;
			int mid;
			int ans=1000000000;
			while(low!=upper){
				count++;
				upper--;
				low--;
				ans--;
				mid=(int)(upper+low)/2;
				System.out.println("?"+mid);
				System.err.println("ans="+ans);
				System.err.println("upper="+upper+" low="+low);
				int r=sc.nextInt();
				if(r==1){
					if(upper==low+1){
						System.out.println("!"+(upper+count));
						sc.close();
						System.exit(0);
					}
					low=mid;
				}else if(r==-1){
					upper=mid;
				}else if(r==0){
					System.out.println("!"+(mid+count));
					sc.close();
					System.exit(0);
				}
			}
		}else if(a==0){
			System.out.println("!100");
			sc.close();
			System.exit(0);
		}

	}
}