from string import ascii_lowercase
from collections import Counter


def request(pre: str):
    for c in ascii_lowercase:
        s = pre+c
        if s in used: continue
        if freq[pre] < 25:
            freq[pre] += 1
            used.add(s)
            print(f'? {s}')
            return

    for c in ascii_lowercase:
        s = pre+c
        if s in used: continue
        freq[pre] += 1
        used.add(s)
        print(f'? {s}')
        break


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

freq = Counter()
used = {c+'a'}
freq[c] += 1

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