import sys
n,h=map(int,input().split())
l=[list(map(int,input().split())) for i in range(n)]
l.sort()
x=l[-1][0]
L=[]
for i in range(n):
  if l[i][1]>x:
    L.append(l[i][1])
L.sort()
L.reverse()
ct=0
for i in range(len(L)):
  h-=L[i]
  ct+=1
  if h<=0:
    print(ct)
    sys.exit()
print(ct+(h+x-1)//x)