N = int(input())
M = N + 1
DP = [1] * M

DP[0] = 0
DP[1] = 0

L = []
for i in range(2, M):
  if DP[i] == 1:
    for j in range(i + i, M, i):
      DP[j] = 0
    k = i
    while k < M:
      k *= i
    k //= i
    L.append(k)

ans = 1

cnt = 0
for n in L:
  print("?", n, flush = True)
  ans *= int(input())
  cnt += 1
  if cnt == 600:
    break

print(ans)