#include<bits/stdc++.h>
using namespace std;
int n,k;
double sum,ans,a[100001],mid;
bool check(double mid){
	sum=0;
	for(int i=1;i<=n;i++){
		if(a[i]>mid){
			sum=sum+a[i]/mid;
		}
	}
    if(sum>=k)return 1;
    else return 0;
}
void qsort(int L,int r){
	int i,j;
	double x;
	i=L;j=r;x=a[(L+r)/2];
	do{
		while(a[i]<x)i++;
		while(a[j]>x)j--;
		if(i<=j){
			swap(a[i],a[j]);
			i++;j--;
		}
	}while(i<=j);
	if(L<j)qsort(L,j);
	if(i<r)qsort(i,r);
}
int main(){
	cin>>n>>k;
	for(int i=1;i<=n;i++)cin>>a[i];
	qsort(1,n);
	double left=0.01,right=a[n];
	while(left<=right){
		mid=(left+right)/2.0;
		if(check(mid)){
			left=mid+0.01;
			ans=mid;
		}
		else right=mid-0.01;
	}
	printf("%.2f",ans);
	return 0;
}

wa了7个点，ac了6个点，为何51分？ dalao看看代码，99孩子吧...