/**

 *

 *作者:Ycute

 *时间:2019-11-01-14.30.12

 *题目简单描述:struct排序

 */

 #include<iostream>

 #include<cmath>

 #include<cstring>

 #include<algorithm>

 #include<vector>

 using namespace std;

 struct shop{

     int num;

     int price;

     double pva;

 };

 bool cmp(struct shop a,struct shop b){

     return a.pva>b.pva;

 }

 int main(){

     struct shop s[];

     int t,nnum;

     scanf("%d %d",&t,&nnum);

     for(int i=;i<t;i++){

         scanf("%d",&s[i].num);

     }

     for(int i=;i<t;i++){

         scanf("%d",&s[i].price);

         s[i].pva=s[i].price*1.0/s[i].num;

     }

     sort(s,s+t,cmp);

     int i=;

     double sum=;

     while(nnum){

         if(s[i].num<=nnum){//充足情况

             sum+=s[i].price;

             nnum-=s[i++].num;

             //cout<<i<<" "<<sum<<endl;

         }else{

             sum+=(s[i].price*1.0/s[i].num)*nnum;

             break;

         }

     }

     printf("%.2lf\n",sum);

     return ;

 }