n,h = map(int,input().split())
a = [0]*n
b = [0]*n
for i in range(n):
  a[i],b[i] = map(int,input().split())
a.sort()
b.sort()
b.reverse()
c = 0
for x in b:
  if x <= a[-1] or h <= 0:
    break
  h -= x
  c += 1
print(c+max(0,(h+a[-1]-1)//a[-1]))