include [HTML_REMOVED]

include [HTML_REMOVED]

using namespace std;
const int N = 100010;
int cow[N];
double s[N];
int n,m;
//定义数组在全局变量
//定义首先要输入的变量
bool check(double mid)
{
for(int i = 1;i<=n;i) s[i] = s[i-1] + cow[i]-mid;
double minv = 0;
for(int i =0,j = m;j<=n;j,i)
{
minv = min(minv,s[i]);
if(s[j]>=minv) return true;
}
return false;
}
int main()
{
cin >> n >> m;
for(int i=1;i<=n;i) cin >> cow[i];
double l = 1,r = 2000;

while(r-l>1e-5)
{
    double mid = (r+l)/2;
    if(check(mid))  l = mid;
    else r = mid;
}
printf("%d",int(r*1000));
return 0;

}