import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = (1 << 63)-1
inf = (1 << 31)-1
# md = 10**9+7
# md = 998244353

def ask(k):
    print("?", k, flush=True)
    a = int(input())
    return 2*a-k

n = II()

lv = ask(1)
rv = ask(n-1)

if lv == rv:
    print("!", 2, n-1, flush=True)
    exit()

l, r = 1, n-1
while 1:
    m = (l+r)//2
    mv = ask(m)
    if mv == 0:
        if m >= n//2:
            print("!", 1, m, flush=True)
        else:
            print("!", m+1, n, flush=True)
        break
    if lv*mv < 0:
        r = m
        rv = mv
    else:
        l = m
        lv = mv