n, h = map(int, input().split())
a = [0]*n
b = [0]*n
for i in range(n):
    a[i], b[i] = map(int, input().split())

A = max(a)
B = sorted([x for x in b if x > A], reverse=True)


cnt = 0
damage = 0
for b in B:
    cnt += 1
    damage += b
    if damage >= h:
        break
else:
    cnt += -(-(h-damage)//A)
print(cnt)
