#include <iostream>
#include <cstdio>
using namespace std;

int main() {
  int tests, k, i, j;
  int num[1000], den[1000];

  while (cin >> tests >> k) {
    if (tests == 0 && k == 0)
      return 0;
    for (i = 0; i < tests; i++)
      cin >> num[i];
    for (i = 0; i < tests; i++)
      cin >> den[i];

    double scores[1000];
    double lb = 0, ub = 1;
    for (i = 0; i < 100; i++) {
      double x = (lb+ub)/2;

      for (j = 0; j < tests; j++) 
	scores[j] = num[j] - x*den[j];
      sort(scores, scores+tests);
      double total = 0;
      for (j = k; j < tests; j++) 
	total += scores[j];

      if (total >= 0)
	lb = x;
      else
	ub = x;
    }

    cout << int(100*lb + 0.5) << endl;
  }
}