#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

typedef double dl;

const int N=;

const dl eps=1e-;

dl a[N],b[N],t[N];

int n,k;

double solve(dl l,dl r){

    while(r-l>eps){

    dl mid=(l+r)/;

    for(int i=;i<=n;i++)t[i]=a[i]-mid*b[i];

    sort(t+,t+n+);

    dl sum=;

    for(int i=k+;i<=n;i++)sum+=t[i];

    if(sum>)l=mid;

    else r=mid;

    }

    return r;

}

int main(){

    while(scanf("%d%d",&n,&k)!=EOF&&n+k){

    for(int i=;i<=n;i++)scanf("%lf",&a[i]);

    for(int i=;i<=n;i++)scanf("%lf",&b[i]);

    printf("%.f\n",solve(,)*);

    }

    return ;

}