n, h,  *ab = map(int, open(0).read().split())
a = ab[::2]
x = max(a)
b = sorted([i for i in ab[1**2] if i > x], reverse=1)
ans = 0
for i in b:
    ans += 1
    h -= i
    if h <= 0:
        break
ans += (h + x - 1) // x
print(ans)
