N,H = map(int, raw_input().split())
x = [None]*(N*2)
for i in range(N):
  a,b = map(int, raw_input().split())
  x[2*i] = (a, 0)
  x[2*i+1] = (b, 1)
x = sorted(x)[::-1]
ans = 0
for t in x:
  if t[1]==0:
    print ans+(H+t[0]-1)/t[0]
    break
  H -= t[0]
  ans += 1
