#include <iostream>

 #include <algorithm>

 #include <functional>

 using namespace std;

 static double mid, y[];

 struct _set

 {

     int a,b;

 }nums[];

 bool judge(const int,const int);

 int main(void)

 {

     int n, k, t;

     double lb, rb;

     while (~scanf("%d%d", &n, &k))

     {

         if (n ==  && k == )

             break;

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

             scanf("%d", &nums[i].a);

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

             scanf("%d", &nums[i].b);

         lb = ; rb = 1.00, t = ;

         while (t--)

         {

             mid = (lb + rb) / ;

             if (judge(k, n)) lb = mid;

             else rb = mid;

         }

         printf("%d\n", int( * rb + 0.5));

     }

     return ;

 }

 bool judge(const int k,const int n)

 {

     double sum = ;

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

         y[i] = nums[i].a - nums[i].b*mid;//把∑a/b>=w移项

     sort(y, y + n);

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

         sum += y[n - i - ];//要选择最大的k个，而不是最小的k个

     return sum > ;

 }