from collections import defaultdict

N=int(input())
ans=["a"]*N
d=defaultdict(int)

for i in range(26):
  t=chr(97+i)*N
  print("?",t,flush=1)
  n=int(input())
  d[chr(97+i)]=n

for i in range(N):
  x=0
  tmp=0
  flag=0
  for j in range(26):
    if d[chr(97+j)]==0:
      continue
    ans[i]=chr(97+j)
    t="".join(ans)
    print("?",t,flush=1)
    n=int(input())
    if n>x:
      x=n
      tmp=j
      if flag:
        break
      flag=1
  ans[i]=chr(97+tmp)
  d[chr(97+tmp)]-=1

print("!","".join(ans))