n, h = map(int, input().split())
e = [[int(i) for i in input().split()] for i in range(n)] 
x=0
a_list = [e[i][0] for i in range(n)]
t_list = [e[i][1] for i in range(n)]
a=max(a_list)
t_list=sorted((i for i in t_list if i >a),reverse=True)
if h>sum(t_list):
  h=h-sum(t_list)
  x=len(t_list)+(-(-h//a))
else:
  for i in range(n):
    h=h-t_list[i]
    if h<=0:
      break
    else:
      x=x+1
print(x)