#include<cstdio>
#define syy myson
using namespace std;
int n,k,a[10010],l,r,mid,i;
int check(int m)
{
	int ans=0;
	for(i=1;i<=n;i++)ans+=(a[i]/m);
	if(ans>=k)return 1;
	else return 0;
}
int Main()
{
	freopen("cable.in","r",stdin);freopen("cable.out","w",stdout);
	scanf("%d%d",&n,&k);
	for(i=1;i<=n;i++)
	{
		double x;
		scanf("%lf",&x);
		a[i]=float(x*100.0);
		if(r<a[i])r=a[i];
	}
	r++;
	while(l+1<r)
	{
		mid=(l+r)/2;
		if(check(mid))l=mid;
		else r=mid;
	}
	printf("%.2lf",l/100.0);
	return 0;
}
int main(){;}
int syy=Main();