from collections import defaultdict

N = int(input())
ans = ['z'] * N
T = ['z'] * N
rem = 2500
for i in range(N):
    cnt = defaultdict(list)
    for d in range(25):
        T[i] = chr(ord('a') + d)
        print(f"? {''.join(T)}", flush=True)
        n = int(input())
        cnt[n].append(T[i])
        rem -= 1
    if len(cnt) == 1:
        continue
    key = max(cnt.keys())
    ans[i] = cnt[key][0]
assert rem >= 0
print(f"! {''.join(ans)}", flush=True)