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()

for i in range(1, n+1):
    day = 1
    f = 1
    while (day-1) * i < n:
        if C[min(n-1, i*day-1)] < day:
            f = 0
            break
        day += 1
    if f:
        ans = i
        break

print(ans)