from re import I


N = int(input())
isp = [i>=2 for i in range(N+1)]
for i in range(2,N+1):
  if not isp[i]:continue
  for j in range(i+i,N+1,i):isp[j] = False
ans = 1
query = 1
cnt = 0
for i in range(2,N+1):
  if not isp[i]:continue
  now = 1
  while now*i <= N:now*=i
  if query*now > N:
    print("?",query,flush=True)
    ans *= int(input())
    cnt += 1
    if cnt > 600:
      assert False
    query = now
  else:
    query *= now
if query > 1:
  print("?",query,flush=True)
  ans *= int(input())
  cnt += 1
  if cnt > 600:
    assert False
print(ans)