n, h = map(int, input().split())
ab = sorted([list(map(int, input().split())) for _ in range(n)], key = lambda x: x[1], reverse = True)

m = sorted(ab, key = lambda x: x[0], reverse = True)[0][0]

ans = 0
for a, b in ab:
    if h > 0 and b >= m:
        h -= b
        ans += 1
    else:
        break

ans += -(-h // m)

print(ans)