N,H=map(int,input().split())
X=[tuple(map(int,input().split())) for i in range(N)]
A=[x[0] for x in X]
B=[x[1] for x in X]
amax=max(A)
B.sort(reverse=True)
ans=0
for b in B:
    if H<=0 or b<=amax:
        break
    if b>amax:
        ans+=1
        H-=b
if H<=0:
    print(ans)
else:
    ans+=(H+amax-1)//amax
    print(ans)