#include<bits/stdc++.h>

using namespace std;

const int N = ;

int n, s;

int b[N], c[N], dp[N];

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", &s);

    memset(dp, 0x3f3f, sizeof(dp));

    dp[] = ;

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

    {

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

        {

            for(int k = s; k >= j * b[i]; --k) dp[k] = min(dp[k], dp[k - j * b[i]] + j);

            c[i] -= j;

        }

        if(c[i]) for(int j = s; j >= c[i] * b[i]; --j) dp[j] = min(dp[j], dp[j - c[i] * b[i]] + c[i]);

    }

    printf("%d\n", dp[s]);

    return ;

}