N, H = map(int, input().split())
ls = []
for i in range(N):
  a, b = map(int, input().split())
  ls += [(a,-b)]
ls.sort(key=lambda x:x[0])
a = ls[-1]
ls = ls[:-1]
ls.sort(key=lambda x:x[1])
ans = 0
for i in range(N-1):
  if ls[i][1]>-a[0]:
    break
  H += ls[i][1]
  ans += 1
  if H<=0:
    break
if H<=0:
  print(ans)
else:
  m = H+a[1]
  ans += 1
  if m<=0:
    print(ans)
  else:
    n = m//a[0] if m%a[0]==0 else m//a[0]+1
    ans += n
    print(ans)
