n, m = map(int, input().split()); assert 1 <= n <= 10**6 and 1 <= m <= 10**9
AB = [list(map(int, input().split())) for _ in range(n)]
for i in range(n): assert 0 <= AB[i][0] <= m and 1 <= AB[i][1] <= 10**9
C = [(m-AB[i][0]) // AB[i][1] + 1 for i in range(n)]
C.sort()
ans = 0
for i in range(n):
    ans = max(ans, (i + C[i]) // C[i])
print(ans)