n,h=map(int,input().split())
A=[]
B=[]
for i in range(n):
  a,b=map(int,input().split())
  A.append(a)
  B.append(b)
A=max(A)
B.sort(reverse=True)
count=0
for i in B:
  if A>i:
    break
  else:
    h-=i
    count+=1
print(count+h//A)