import numpy as np

np.random.seed(998998)

def query(s: list[str]) -> int:
    print('?', ''.join(s))
    return int(input())

N = int(input())

ret = ['a'] * N

v = query(['a'] * N)

for idx in range(N):
    qs = list(range(1, 26))
    np.random.shuffle(qs)

    for d in qs:
        tmp = ['a'] * N
        tmp[idx] = chr(ord('a') + d)
        if query(tmp) > v:
            ret[idx] = chr(ord('a') + d)
        elif query(tmp) < v:
            break

print('!', ''.join(ret))