N,H=map(int,input().split())
c=[list(map(int,input().split()))for _ in[0]*N]
a=max(r[0]for r in c)
b=sorted(r[1]for r in c if r[1]>a)
n=0
while H>0 and b:
    H-=b.pop()
    n+=1
print(n+max(H-1,-1)//a+1)