N, H = map(int, input().split())
a, b = [0] * N, [0] * N
for i in range(N):
    a[i], b[i] = map(int, input().split())
a.sort(reverse=True)
b.sort(reverse=True)
ans = 0
index = 0
while len(b) > index and b[index] > a[0]:
    H -= b[index]
    index += 1
    ans += 1
ans += (H + a[0] - 1) // a[0]
print(ans)
