n,h=map(int,input().split())
l=[[map(int,input().split())] for _ in range(n)]
la=sorted(l,key=lambda x:x[0],reverse=True)
a=l[0][0]
lb=sorted(l,key=lambda x:x[1],reverse=True)
count=0
total=0
for i in lb:
    if i[1]>a:
        count+=1
        total+=i[1]
    else:
        break
print((h-total)//a+1+count