#D
import numpy as np
n,h = map(int,input().split())
a,b = [0]*n,[0]*n
for i in range(n):
    a[i],b[i] = map(int,input().split())
amax=max(a)
bp = [i for i in b if i>amax]
bp.sort(reverse=True)
sumbp=sum(bp)
if sumbp<h:#投げれるだけ投げてのこりを切る
    print( (h-sumbp)//amax + len(bp) )
else:#投げまくる
    rest=h
    i=0
    while rest>0:
        rest -=b[i]
        i+=1
    print(i)