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