using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        WriteLine("? 0");
        var abs = NN;
        WriteLine($"? 1");
        var one = NN;
        if (abs < one) abs = -abs;
        WriteLine($"! {abs}");
    }
}