N,H = map(int,input().split())
K = [list(map(int,input().split())) for n in range(N)]
A = max(k[0] for k in K)
B = sorted(b for a,b in K if A<b)
C = 0

while 0<H and B:
  H-=B.pop()
  C+=1

print(C-(-max(0,H)//A))