n, m = [int(x) for x in input().split()]
ab = [[int(x) for x in input().split()] for _ in range(n)]
k = [(m - ai) // bi + 1 for ai, bi in ab]
k.sort()
lf = 0
rg = n
while rg - lf > 1:
	md = (lf + rg) // 2
	if any(ki <= li for ki, li in zip(k, (i // md for i in range(n)))):
		lf = md
	else:
		rg = md
print(rg)