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 in range(len(B)):
    H -= B[i]
    if H <= 0:
        break
else:
    i += (H + a - 1) // a
i += 1
print(i)