import math

N, H = map(int, input().split())
a = []
b = []
for i in range(N):
	ip = list(map(int, input().split()))
	a.append(ip[0])
	b.append(ip[1])

a.sort()
a.reverse()
b.sort()
b.reverse()
ptr = 0
cnt = 0

while(ptr < N and a[0] <= b[ptr]):
	H -= b[ptr]
	ptr+=1
	cnt+=1

cnt += math.ceil(H / a[0])
print(cnt)