import math

n, h = map(int, input().split())
ba = [tuple(map(int, reversed(input().split()))) for i in range(n)]
ba.sort(reverse = True)

ans = 2000000000

bs = [0]
for i in range(n):
    bs.append(bs[i] + ba[i][0])
    if bs[i + 1] >= h:
        ans = min(ans, i + 1)


for i in range(n):
    b, a = ba[i]

    L = i
    R = n
    while (R - L > 1):
        M = (L + R) // 2
        if ba[M][0] < a:
            R = M
        else:
            L = M
    ans = min(ans, R + math.ceil((h - bs[R]) / a))

print(ans)