n, h, *t=map(int,open(0).read().split())
a = sorted(t[::2])
b = sorted(t[1::2])
b_high = [i for i in b if i >= max(a)]
if (h - sum(b_high)) % a[-1] == 0:
  print(len(b_high) + (h - sum(b_high)) // a[-1])
else:
  print(len(b_high) + ((h - sum(b_high)) // a[-1]) + 1)