import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int p = 0; int l = 0; int r = (int)Math.pow(10, 9) + 1; int ans = 0; while(l < r) { int med = (l + r) / 2; System.out.println("? " + med); System.out.flush(); int t = sc.nextInt(); if(t == -1) { r = med - 1; p++; } else if(t == 1) { l = med; p++; } else { ans = med + p; System.out.println("! " + ans); System.out.flush(); break; } } } }