from math import ceil
n, h = map(int, input().split())
a = []
b = []
for i in range(n):
  p, q = map(int, input().split())
  a.append(p)
  b.append(q)
b.sort(reverse=1)
ans=0
m=max(a)
while(h>0 and len(b) != 0):
  if b[0] < m:
    break
  h-=b[0]
  b.pop(0)
  ans+=1
if h>0:
  ans+=ceil(h/m)
print(ans)