mod = 1000000007 eps = 10**-9 def main(): import sys input = sys.stdin.readline def ask(k): print("?", k) sys.stdout.flush() return int(input()) N = int(input()) s0 = ask(N // 2) if s0 * 2 == N or s0 == 0: print("!", 2, N - 1) sys.stdout.flush() exit() s0 = s0 - (N // 2 - s0) l = N // 2 r = N + 1 for _ in range(19): mid = (l + r) // 2 s = ask(mid) s = s - (mid - s) if s == 0: print("!", 1, mid) sys.stdout.flush() exit() if s * s0 > 0: l = mid else: r = mid if __name__ == '__main__': main()