N,HP=map(int,input().split())
listK=[]
listN=[]

for i in range(N):
    k,n=map(int,input().split())
    listK.append(k)
    listN.append(n)
listK.sort(reverse=True)
listN.sort(reverse=True)
cnt=0
for j in range(N):
    if listN[j]>=max(listK):
        HP-=listN[j]
        cnt+=1
        if HP<=0:
            print(cnt)
            exit()
    else:
        break

cnt+=int((HP+listK[0]-1)/(listK[0]))
print(cnt)
