#include<bits/stdc++.h>
using namespace std;
#define int long long
int a[10001];
int n,k;
bool check(int x){
	int cnt = 0;
	for (int i = 1; i <= n; i++) cnt += a[i] / x;
	return cnt < k;
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> k;
	int l = 1,r = 0;
	for (int i = 1; i <= n; i++){
		double x;
		cin >> x;
		a[i] = x * 100;
		r = max(r,a[i]);
	} 
	while (r - l > 1){
		int mid = (l + r) / 2;
		if (check(mid)) r = mid;
		else l = mid;
	}
	printf("%.2lf",l / 100.0);
	return 0;
}