6

#include<bits/stdc++.h>
using namespace std;
double a[10001];
int main()
{
	int n,i,k,z,x=10000000,y=0,mid;
	double w=0;
	cin>>n>>k;
	for(i=1;i<=n;i++){
		cin>>a[i];
		a[i]=a[i]*100;
	}
	while(x>=y){
		z=0;
		mid=(x+y)/2;
		for(i=1;i<=n;i++)
			z+=a[i]/mid;
		if(z<k)x=mid-1;
		else{
			y=mid+1;
			if(mid>w)w=mid;
		}
	}
	printf("%.2lf",w/100);
	return 0;
}