import sys
import os
import math

N, H  = map(int,input().split())
katana = [0 for _ in range(N)]

for i in range(N):
    a,b = map(int,input().split())
    katana[i] = [a,b]
katana = sorted(katana,key=itemgetter(1),reverse=True)
maxA = 0
for i in range(N):
    maxA = max(maxA,katana[i][0])

cnt = 0
for k in katana:
    if H <= 0:
        print(cnt)
        sys.exit()
    if k[1] > maxA:
        H -= k[1]
        cnt += 1
cnt += math.ceil(H/maxA)
print(cnt)
