n,h=map(int,input().split())
ab=[]
b_sum=0
ans=0
for i in range(n):
  aa,bb=map(int,input().split())
  ab.append([aa,bb])
  b_sum+=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
for a,b in ab:
  if b>katana:
    cnt+=1
ans+=cnt
for i in range(cnt):
  h-=ab[i][1]

from math import ceil
ans+=ceil(h/katana)
print(ans)