#include <bits/stdc++.h>
using namespace std;

pair<double, double> a[1010];
int n, d;

int main()
{
    cin >> n >> d;
    for (int i = 0; i < n; i++) cin >> a[i].first;
    for (int i = 0; i < n; i++) cin >> a[i].second, a[i].second /= a[i].first; //计算单价

    sort(a, a + n, [](auto &x, auto &y) {
        return x.second > y.second; //按单价从高到底排序
    });

    double sum = 0;
    int i = 0;
    while (d && i < n) //一斤斤买
    {
        if (a[i].first)
        {
            sum += a[i].second;
            a[i].first--;
            d--;
        }
        else
        {
            i++;
        }
    }
    printf("%.2lf", sum);

    return 0;
}