n, H = map(int, input().split())
amax = 0
ab = []

for i in range(n):
    v1, v2 = map(int, input().split())
    amax = max(amax, v1)
    ab.append([v1, v2])

ab.sort(key=lambda x: x[1], reverse=True)
cnt = 0

#print(ab)

while H > 0 and len(ab) > 0:
    if len(ab) == 1 and ab[0][1] < H:
        if ab[0][0] == amax:
            cnt += H // amax
            break
        else:
            H -= ab[0][0]
            cnt += 1
    elif ab[0][1] > amax:
        H -= ab[0][1]
        del ab[0]
        cnt += 1
    else:
        cnt += H // amax
        break

print(cnt)

