import math
n,m=map(int,input().split())
a=[]
for i in range(n):
  b,c=map(int,input().split())
  a.append([b,c])
a.sort()
ans=0
for i in range(n-1):
  m-=a[i][1]
  ans+=1
  if m<=0:
    break
a1=a[n-1][0]
b1=a[n-1][1]
ans+=1
if m-b1>=0:
  ans+=math.ceil((m-b1)/a1)
print(ans)  
	