N,H=map(int,input().split())
A=[]
B=[]
for i in range(N):
    AB=list(map(int,input().split()))
    A.append(AB[0])
    B.append(AB[1])

B.sort(reverse=True)
Amax=max(A)
ans=0

for i in range(N):
    if B[i]<Amax:
        break

    H-=B[i]
    ans+=1
    if H<=0:
        break

if H>0:
    ans=ans+(-(-H//Amax))

print(ans)