#pragma comment(linker, "/STACK:1024000000,1024000000")#include<cstdio>#include<cstring>#include<cmath>#include<algorithm>#include<vector>#include<map>#include<set>#include<queue>#include<stack>#include<ctime>#include<iostream>using namespace std;typedef long long LL;const double pi=acos(-1.0),eps=1e-10;void File(){    freopen("D:\\in.txt","r",stdin);    freopen("D:\\out.txt","w",stdout);}template <class T>inline void read(T &x){    char c = getchar();    x = 0;    while(!isdigit(c)) c = getchar();    while(isdigit(c))    {        x = x * 10 + c - ‘0‘;        c = getchar();    }}int n,k;double a[100010],s[100010];int q[100010],f1,f2;bool delete1(int a,int b,int c){    if((s[c]-s[a])*(c-b)<(s[c]-s[b])*(c-a)) return 1;    return 0;}bool delete2(int a,int b,int c){    if((s[c]-s[b])*(b-a)<(s[b]-s[a])*(c-b)) return 1;    return 0;}int main(){    while(~scanf("%d%d",&n,&k))    {        for(int i=1;i<=n;i++) scanf("%lf",&a[i]);        for(int i=1;i<=n;i++) s[i]=s[i-1]+a[i];        f1=0; f2=0; q[f2]=0; double ans=0;        for(int i=k;i<=n;i++)        {            while(1)            {                if(f2-f1+1<2) break;                if(delete1(q[f1],q[f1+1],i)) f1++;                else break;            }            ans=max(ans,1.0*(s[i]-s[q[f1]])/(i-q[f1]));            while(1)            {                if(f2-f1+1<2) break;                if(delete2(q[f2-1],q[f2],i)) f2--;                else break;            }            f2++; q[f2]=i-k+1;        }        printf("%d\n",(int)(1000*ans));    }    return 0;}