def main():
    N, H = map(int, input().split())
    AB = tuple(tuple(map(int, input().split())) for _ in [0] * N)

    a = []
    apnd_a = a.append
    b = []
    apnd_b = b.append
    for i, j in AB:
        apnd_a(i)
        apnd_b(j)

    a = max(a)
    b.sort(reverse=True)
    b = [0] + b
    energy = H
    ans = float('inf')
    for i, j in enumerate(b):
        energy -= j
        if energy <= 0:
            print(i)
            return
        x = i
        x += (energy + a - 1) // a
        ans = min(ans, x)
    print(ans)

main()
