n,h=map(int,input().split())
ab=[]
s=0
for i in range(n):
    ab.append([int(j) for j in input().split()])
    s+=ab[-1][1]
    
ab.sort()
fm=ab[-1][0]
nm=ab[-1][1]

from operator import itemgetter
ab.sort(key=itemgetter(1)) 
ab.reverse()

ans=0

if s>=h:
    p=0
    i=0
    while p<h:
        p+=ab[i][1]
        ans+=1
        i+=1
else:
    ab.reverse()
    s=0
    for i in range(n):
        if ab[i][1]>=fm:
            s+=ab[i][1]
            ans+=1
    import math
    ans+=math.ceil((h-s)/fm)

print(ans)


