N,H=map(int,input().split())
S=[[int(x) for x in input().split()] for _ in range(N)]
A,B=zip(*S)
A=max(A)
B=[b for b in B if b>A]
B.sort(reverse=True)
ans=0
cnt=0
for b in B:
    if H<=0:
        break
    cnt+=1
    H-=b
if H>0:
    cnt+=(H-1)//A+1
print(cnt)