from operator import itemgetter
import math
N,H = [int(x) for x in input().split()]
ab = [[int(x) for x in input().split()]for _ in range(N)]
ab.sort(key = itemgetter(1),reverse = True)
left = H
cnt = 0
max_a = max(ab,key=itemgetter(0))[0]

for i in ab:
    if(i[1]>max_a):
        left -= i[1]
        cnt += 1
    else:
        cnt += math.ceil(left/max_a)
        break
if(left>0):
    cnt += math.ceil(left/max_a)
print(cnt)
