N, H = map(int, input().split())
A, B = zip(*[tuple(map(int, input().split())) for _ in range(N)])
a = max(A)
B = sorted((b for b in B if b > a), reverse=True)
for i, b in enumerate(B, 1):
    H -= b
    if H <= 0:
        ans = i
        break
else:
    ans = len(B) + (H + a - 1) // a
print(ans)