n, M = map(int, input().split(' '))
ab = [tuple(map(int, input().split(' '))) for _ in range(n)]

l, r = 0, 2*10**9
while l < r:
	m, p = (l + r) // 2, 0
	for a, b in ab:
		p += max(0, a * m - b)
	if p >= M:
		r = m
	else:
		l = m + 1

print(l)