from string import ascii_lowercase


def request(pre: str):
    for c in ascii_lowercase:
        s = pre+c
        if s in used: continue
        print(f'? {s}')
        break


c = input()
print(f'? {c}a')

used = {c+'a'}
while 1:
    _, s = input().split()
    if s in ['WIN', 'LOSE']: break
    used.add(s)
    request(s[-1])