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 now_nums.get(n)==None:
      now_nums[n]=[cha]
    else:
      now_nums[n].append(cha)

    if cha_num>=2 and len(now_nums)==2:
      for key in now_nums:
        if len(now_nums[key])==1:
          kaku[i] = now_nums[key][0]
          flag = True
          break

print(*kaku)