def query(X):
  print("? {}".format(X))
  return input()=="out"

def answer(X):
  print("! {}".format(X))

if __name__ == '__main__':
  safe, out = 0, 10**3
  while abs(safe-out) > 1:
    mid = (safe+out)//2
    isAngry = query(mid)
    if isAngry:
      isAngry = query(mid+1)
      if isAngry:
        out = mid
      else:
        safe = mid+1
    else:
      safe = mid
  answer(safe)