import java.util.*; class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int min = 0; int max = 1000000000; while(min <= max) { System.out.println("? " + (min + max)/2); int in = sc.nextInt(); if(in == 1) { min = (min + max)/2+1; } else { max = (min + max)/2-1; } } System.out.println("! " + max); } }