N, H = map(int, input().split())
AB = [list(map(int, input().split())) for _ in range(N)]
A = [i[0] for i in AB]
A.sort()
B = [i[1] for i in AB]
B.sort()

furudamage = A[-1]
count= 0
while len(B) > 0:
    nagedamage = B.pop()
    if nagedamage > furudamage:
        H -= nagedamage
        count += 1
        if H <= 0:
            print(count)
            break
    else:
        break
if H > 0:
    count += round(H/furudamage)
    print(count)
