rt

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 5;

int n, k, a[N];

bool check(int mid, int k){
	int sum = 0;
	for (int i = 0; i < n; i++)
		sum += a[i] / mid;
	return sum >= k;
}

int main(){
	cin >> n >> k;
	double num;
	for (int i = 0; i < n; i++){
		cin >> num;
		a[i] = int (num * 100);
	}
	sort(a, a + n);
	int l = 1, r = a[n - 1];
	int mid, ans;
	while (l <= r){
		mid = (r + l) / 2;
		if (check(mid, k))
			l = mid + 1, ans = mid;
		else
			r = mid - 1;
	}
	printf("%.6f", ans / 100.0);
	return 0;
}