#nullable enable

#region
var _input = Array.Empty<string>();
var _iter = 0;
string String()
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Split(' '), 0);
    return _input[_iter++];
}
T I<T>() where T : IParsable<T> => T.Parse(String(), null);
#endregion

int J(int i)
{
    var c = (char)(i + 'A');
    var bag = new Bag<int>();
    while (true)
    {
        Console.WriteLine($"? {c}");
        var z = I<int>();
        bag.Add(z);
        if (bag[z] == 12) return z;
    }
}

int A(int i1, int i2, int i3, int es)
{
    var c1 = (char)(i1 + 'A');
    var c2 = (char)(i2 + 'A');
    var c3 = (char)(i3 + 'A');
    while (true)
    {
        Console.WriteLine($"+ {c1} {c2} {c3}");
        if (String() != "0") return 1;
        if (J(i3) == es) return 0;
    }
}

void F(int i) => Console.WriteLine($"! {(char)(i + 'A')}");

var e = new int[3];
var a = J(0);
var b = J(1);
if (b == 1)
{
    F(0);
    return;
}
A(2, 2, 1, 0);
A(0, 2, 1, a);
A(0, 0, 2, a + a);
e[0] = e[1] = 1;
e[2] = 2;
while (true)
{
    var max = e.Max();
    var min = e.Min();
    var maxi = -1;
    var mini = -1;
    for (var i = 0; i < 3; i++)
    {
        if (e[i] == max) maxi = i;
        if (e[i] == min) mini = i;
    }
    if (max == b)
    {
        F(maxi);
        return;
    }
    var oi = 3 - maxi - mini;
    var o = e[oi];
    var ar = 0;
    if ((b - max) % o == 0)
    {
        ar = A(oi, maxi, mini, a * (max + o));
        e[mini] = max + o;
    }
    else
    {
        ar = A(mini, maxi, oi, a * (max + min));
        e[oi] = max + min;
    }
    if (ar != 0)
    {
        F(0);
        return;
    }
}

class Bag<K> where K : notnull
{
    readonly Dictionary<K, int> _dictionary = new();
    public void Add(K key)
    {
        var dictionary = _dictionary;
        if (dictionary.TryGetValue(key, out var count)) dictionary[key] = count + 1;
        else dictionary[key] = 1;
    }
    public bool Remove(K key)
    {
        var dictionary = _dictionary;
        if (!dictionary.TryGetValue(key, out var count)) return false;
        if (count == 1) dictionary.Remove(key);
        else dictionary[key] = count - 1;
        return true;
    }
    public int this[K key] => _dictionary.TryGetValue(key, out var count) ? count : 0;
    public int CountKeys => _dictionary.Count;
}