import math

n, h = map(int, input().split())
array = [[int(x) for x in input().split()] for x in range(n)]

array = sorted(array, key=lambda x:x[0], reverse=True)
tmp_a = array[0][0]
array = sorted(array, key=lambda x:x[1], reverse=True)
cnt = 0
for a, b in array:
    if b > tmp_a:
        h -= b
        cnt += 1
    else:
        break
print(cnt+math.ceil(h/tmp_a))
