N = int(input())
l, r = 1, N
al, ar = 1, N - 1
while l + 1 < r:
	m = (l + r) // 2
	print('?', m)
	am = int(input())
	if am - al < m - l:
		r = m
		ar = am
	else:
		l = m
		al = am
print("Yes", l, r)