from collections import defaultdict
a = input()
lib = defaultdict(lambda: False)
lib[a*2] = True
print("?", a*2)

while True:
    status, s = input().split()
    if status == "!": break
    a = s[-1]
    for i in range(26):
        string = a + chr(97 + i)
        if not lib[string]:
            print("?", string)
            break