n,h = map(int,input().split())
al=[]
bl=[]
for _ in [0]*n:
  a,b = map(int,input().split())
  al.append(a)
  bl.append(b)
al.sort()
bl.sort()
ans = 0
while h>0:
  if len(bl)>0 and bl[-1]>al[-1]:
    h-=bl[-1]
    ans+=1
    del bl[-1]
  else:
    ans += -(-h//al[-1])
    h=0
print(ans)