#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<vector>
using namespace std;
typedef __int64 LL;
const int MAXN=1005;
int a[MAXN],b[MAXN];
const double eps=1e-4;
int n,k;
bool check(double val) {
	double ans=0;
	vector<double> tmp;
	for(int i=0;i<n;i++) {
		ans+=(1.0*100*a[i]-1.0*val*b[i]);
		tmp.push_back(1.0*100*a[i]-1.0*val*b[i]);
	}
	sort(tmp.begin(),tmp.end());
	for(int i=0;i<k;i++) ans-=tmp[i];
	return ans>-eps;
}
int main() {
	while(~scanf("%d%d",&n,&k)&&(n||k)) {
		double l=0,r=100,ans=-1;
		for(int i=0;i<n;i++) scanf("%d",&a[i]);
		for(int i=0;i<n;i++) scanf("%d",&b[i]);
		while(r-l>eps) {
			double mid=(l+r)/2;
			if(check(mid)) l=ans=mid;
			else r=mid;
		}
		printf("%.0f\n",ans);
	}
	return 0;
}