N, H = [int(_) for _ in input().split()]
max_a = 0
B = []
for i in range(N):
    a, b = [int(_) for _ in input().split()]
    max_a = max(a, max_a)
    B.append(b)

ans = 0
B.sort(reverse=True)

for i in range(N):
    if B[i] > max_a:
        H -= B[i]
        ans += 1
    else:
        break

if H > 0:
    cnt = H // max_a
    H -= cnt * max_a
    if H > 0:
        H -= max_a
        cnt += 1
    ans += cnt
print(ans)
