#include <bits/stdc++.h>
using namespace std;
int n, k;
int a[10005];
double b;
bool pd(int mid)
{
long long cnt = 0;
for (int i = 1; i <= n; i++)
cnt += a[i] / mid;
return cnt >= k;
}
int main()
{
cin >> n >> k;
for (int i = 1; i <= n; i++)
{
scanf("%lf", &b);
a[i] = round(b * 100);
}
int l = 1, r = 10000000;
int ans = 0;
while (l <= r)
{
int mid = l + r >> 1;
if (pd(mid))
{
ans = mid;
l = mid + 1;
}
else
r = mid - 1;
}
printf("%.2lf", ans / 100.0);
return 0;
}