from collections import deque

def main(x):
    num = int(x)
    l.append(num)
    flg = max(l) % 2

    if max(l) == num:
        a_list = [i for i in range(num)]
        d = deque(a_list)
        a=d.pop()
        b=d.pop()
        return '? 0 1'
    else:
        if x == a or x == b:
            if x == a:
                print('!',b)
            else:
                print('!',a)
        else:
            a=d.pop()
            b=d.pop()
            return print('?',a,b)

if __name__ == "__main__":
    l=[]
    print(main(input()))