n, h = [int(t) for t in input().split()]
aa = []
bb = []
for _ in range(n):
    a, b = [int(t) for t in input().split()]
    aa.append(a)
    if b > a:
        bb.append(b)
aa.sort()
bb.sort()

cnt = 0
while h > 0:
    if not bb:
        cnt += (h - 1) // aa[-1] + 1
        break
    elif bb[-1] > aa[-1]:
        h -= bb.pop()
    else:
        h -= aa[-1]
    cnt += 1
print(cnt)
