practice B

atcoder-practice-B.py

from sys import stdout as sys

n, q = map(int, input().split())
k = list("abcdefghijklmnopqrstuvwxyz"[:n])
cn = 0

memo = {}

def comp(a, b):
  global cn
  if a+b in memo:
    return memo[a+b]
  if b+a in memo:
    return not memo[a+b]
  if cn >= q:
    raise Exception()
  cn += 1
  print("? %s %s" % (a, b))
  sys.flush()
  ans = input()
  memo[a+b] = ans == ">"
  return memo[a+b]

def swap(t, p1, p2):
  t[p2], t[p1] = t[p1], t[p2]

def main():
  lim = len(k)
  try:
    for i in range(lim):
      flag = True
      for c in range(lim - i - 1):
        if comp(k[c], k[c + 1]):
          swap(k, c, c + 1)
          flag = False
      if flag:
        break
  except: pass
  print('! '+''.join(k).upper())

main()