a = input()
s = set()
C = [0] * 26
t = a * 2
s.add(t)
i = ord(a) - ord('a')
C[i] += 1
print('?', t, flush = True)
while True:
    b = input()
    if b[0] == '?':
        _, t = b.split()
        s.add(t)
        i = ord(t[0]) - ord('a')
        C[i] += 1
    else:
        break
    if C[i] == 26:
        for j in range(26):
            t = chr(j + ord('a')) + chr(i + ord('a'))
            if t not in s:
                print('?', t, flush = True)
    else:
        i = ord(t[1]) - ord('a')
        if C[i] == 0:
            t = chr(i + ord('a')) + chr(i + ord('a'))
            s.add(t)
            C[i] += 1
        else:
            c = 0
            for i in range(26):
                for j in range(26):
                    if C[j] == 25:
                        continue
                    t = chr(i + ord('a')) + chr(i + ord('a'))
                    if t in s:
                        continue
                    s.add(t)
                    print('?', t, flush = True)
                    c = 1
                    break
            if c:
                break