#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<algorithm>

 using namespace std;

 const int MAXN=+;

 const int INF=*+;

 int n,val,b[MAXN],c[MAXN];

 int f[MAXN];//凑出纸值x的面值数量 

 int main()

 {

     scanf("%d",&n);

     for (int i=;i<=n;i++) scanf("%d",&b[i]);

     for (int i=;i<=n;i++) scanf("%d",&c[i]);

     scanf("%d",&val);

     f[]=;

     for (int i=;i<=val;i++) f[i]=INF;

     for (int i=;i<=n;i++)

         for (int k=;c[i];k<<=)

         {

             k=min(k,c[i]);

             c[i]-=k;

             for (int j=val;j>=k*b[i];j--)

                 f[j]=min(f[j],f[j-k*b[i]]+k);

         }

     printf("%d",f[val]);

     return ;

 }