n,h = map(int, input().split())
A = 0
B = []
for _ in range(n):
    a,b = map(int, input().split())
    if A < a: A = a
    B.append(b)
B.sort(reverse=True)
cnt = 0
for i in B:
    if A < i: 
        h -= i
        cnt += 1
    if h <= 0:
        print(cnt)
        exit()
print(cnt+(h+A-1)//A)