import math

N = int(input())

list = []

for a in range (N - 1):
    print("?", a, N - 1)
    list.append(int(input()))

p = []
i = []
for j in range(len(list)):
    if list[j] != 0:
        p.append(list[j])
        i.append(j)
        if len(p) == 2:
            break

if len(p) == 2:
    print("?", i[0], i[1])
    [a, b] = p
    c = int(input())
    num = int(math.isqrt(a * b // c))
    X = 10 ** (N - 1) * num
    for i in range(N - 1):
        X += (list[i] * 10 ** i) // num
    print("!", int(X))
elif len(p) == 1:
    [a] = p
    if a in [1, 25, 49, 64, 81]:
        num = int(math.isqrt(a))
        X = 10 ** (N - 1) * num
        for i in range(N - 1):
            X += (list[i] * 10 ** i) // num
        print("!", int(X))
    else:
        print("!", -1)
else:
    print("!", -1)