n, h = map(int, input().split())

a = 0
b = []
for i in range(n):
    A, B = map(int, input().split())
    a = max(a, A)
    b.append(B)
b = sorted([i for i in b if a < i], reverse=True)

cnt = 0
for i in b:
    cnt += 1
    h -= i
    if h <= 0:
        print(cnt)
        exit()
print(cnt + (h + a - 1) // a)
