N, H = map(int, input().split())
a = [0] * N
b = [0] * N
for i in range(N):
    a[i], b[i] = map(int, input().split())

a_max = max(a)
b.sort(reverse=True)

c = 0
for i in range(N):
    if b[i] > a_max:
        H -= b[i]
        c += 1
    if H <= 0:
        break

if H > 0:
    c += (H + a_max - 1) // a_max

print(c)
