#include <iostream>
#include <iomanip>
using namespace std;

int n,k;
double arr[10005];

bool check(double l){
	int sum=0;
	for(int i=1;i<=n;++i){
		sum+=arr[i]/l;
	}if(sum>=k){
		return true;
	}return false;
}

int main(){
	cout<<fixed<<setprecision(2);
	cin>>n>>k;
	for(int i=1;i<=n;++i){
		cin>>arr[i];
	}double l=0,r=100000.01;
	while(r-l>=0.003){
		double mid=(l+r)/2;
		if(check(mid)){
			l=mid;
		}else{
			r=mid;
		}
	}for(;l<=r;l+=0.001){
		if(check(l)){
			cout<<l;
			return 0;
		}
	}return 0;
}