from collections import defaultdict
def ask(cnt, var):
    best_cnt = 0
    result = -1
    Cnts = defaultdict(int)
    for i in range(cnt):
        print("?", var)
        x = int(input())
        Cnts[x] += 1
        if(Cnts[x] > best_cnt):
            best_cnt = Cnts[x]
            result = x
    return result
ask_cnt = 20
x = ask(ask_cnt, "A")
y = ask(ask_cnt, "B")

A = x
B = y
C = 0

for i in range(2):
    while True:
        if(i % 2 == 0):
            print("+", "A", "C", "B")
            z = int(input())
            if(z != 0):
                exit()
            result = ask(ask_cnt, "B")
            if(result == x * (i + 1)):
                break
        else:
            print("+", "A", "B", "C")
            z = int(input())
            if(z != 0):
                exit()
            result = ask(ask_cnt, "C")
            if(result == x * (i + 1)):
                break
print("!", "CB"[y % 2])