ALP = "abcdefghijklmnopqrstuvwxyz"

alp = []
for i in range(len(ALP)):
  alp.append(ALP[i])
alp = tuple(alp)

import random

rand_num = 1000

rand_alp = []

for i in range(rand_num):
  rand_alp.append(tuple(random.sample(alp, 26)))

N=int(input())
base = ["a" for i in range(N)]

kaku = [None for i in range(N)]

# from collections import defaultdict

for i in range(N):
  order = random.choice(rand_alp)
  now_nums = dict()
  flag = False
  for cha_num in range(26):
    if flag: break
    cha = order[cha_num]
    T = base[:]
    T[i] = cha
    print("?", "".join(T))
    n=int(input())
    if n not in now_nums:
      if cha_num==0 or cha_num==1:
        now_nums[n] = 1
      else:
        kaku[i] = cha
        flag = True
    else:
      if cha_num==2 and len(now_nums)==2:
        for key in now_nums:
          if now_nums[key]==1:
            kaku[i] = cha
            flag = True
            break

print(*kaku)