N,H=map(int,input().split())
a=[0]*N
b=[0]*N
for i in range(N):
    a[i],b[i]=map(int,input().split())
b.sort(reverse=True)
a.sort(reverse=True)
cnt=0
for i in range(N):
    H=H-b[i]
    cnt+=1
    if H<=0:
        break

if H>0:
    if H%a[0]==0:
        cnt+=H//a[0]
    else:
        cnt+=H//a[0]+1
print(cnt)