n,h=map(int,input().split())
ab=[]
ans=0
for i in range(n):
  aa,bb=map(int,input().split())
  ab.append([aa,bb])

ab.sort(key=lambda x: x[0],reverse=True)
katana=ab[0][0]
ab.sort(key=lambda x: x[1],reverse=True)
cnt=0
# print(ab)
for a,b in ab:
  if b>katana:
    cnt+=1

for i in range(cnt):
  if h<0:break
  h-=ab[i][1]
  ans+=1
if h>0:
  from math import ceil
  ans+=ceil(h/katana)
print(ans)