import java.util.*; public class Main{ public static void main(String[] V){ Scanner sc = new Scanner(System.in); int L = 1; int R = 1000000001; while(R - L > 1){ int C = (L + R) / 2; System.out.println("? " + C); System.out.flush(); int isOK = sc.nextInt(); if(isOK == 0){ L = C; }else{ R = C; } } System.out.println("! " + R); System.out.flush(); } }