import math
n, h = map(int, input().split())
a, b = zip(*(map(int, input().split()) for _ in range(n)))
m = max(a)
r = 0
for i in sorted(b)[::-1]:
    if h<=0 or i<=m:
        break
    h -= i
    r += 1
print(r + math.ceil(max(h, 0)/m))