n = int(input())

IsPrime = [True for _ in range(n + 1)]
IsPrime[0] = IsPrime[1] = False
for i in range(2, n + 1):
    if IsPrime[i]:
        for j in range(i + i, n + 1, i):
            IsPrime[j] = False

Primes = []
for i in range(n + 1):
    if IsPrime[i]:
        Primes.append(i)

ans = 1
for prime in Primes:
    print(f"? {prime}")
    g = int(input())
    if g == 1:
        continue
    curr = prime
    while True:
        curr *= prime
        print(f"? {curr}")
        if g != curr:
            ans *= curr
            break
print(f"! {ans}")