#include<iostream>
#include<cmath>
#include<iomanip>
using namespace std;
int n, k;
double num[10001];
bool find(double x)
{
	int qum = 0;
	for (int i = 0; i < n; i++)
		qum += (int)(num[i] / x);
	if (qum >= k)
		return true;
	return false;
}
int main()
{
	double sum;
	while (cin >> n >> k)
	{
		if (n == 0 && k == 0)
			break;
		sum = 0;
		double max = 0;
		for (int i = 0; i < n; i++)
		{
			cin >> num[i];
			if (num[i] > max)
				max = num[i];
		}
		
		double l = 0, r = max;
		double m;
		for(int i=1;i<100;i++)
		{
			m = (l + r) / 2;
			if (find(m))
				l = m;
			else
			{
				r = m;
			}
		}
		cout <<fixed<<setprecision(2)<< l<<endl;
	}
	return 0;
}