N = int(input())
left = 1
right = N

for q in range(10):
    if right - left == 1:
        print("?", 1)
        x = int(input())
        continue

    mid = (left + right) >> 1
    print("?", mid)
    x = int(input())

    if x >= mid:
        left = mid
    else:
        right = mid

print("Yes", left, right)