N,H = map(int,input().split())
A=[]
B=[]
for i in range(N):
  a,b=map(int,input().split())
  A +=[a]
  B +=[b]
A=sorted(A,reverse=True)
B=sorted(B,reverse=True)
C=A[0]
count=0
for i in range(N):
  if B[i]>=C:
    H -=B[i]
    count +=1
    if H<=0:
      print(count)
      exit()
answer=count-(-H//C)
print(answer)
