import java.io.*;
import java.util.*;

public class LammertTranscribed {
    public static void main(String[] args) throws IOException {
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(System.in))) {
            new LammertTranscribed().run(new Scanner(reader));
        }
    }

    public void run(Scanner sc) throws IOException {
        int n = sc.nextInt(), m = sc.nextInt();

        List<Float> fs = new ArrayList<>();
        long t = 0;
        for (int i = 0; i < n; i++)
        {
            int x = sc.nextInt();
            t += (m * x) / 1000 + ((m * x) % 1000 == 0 ? 0 : 1);
            int maxv = (m * x) / 1000;
            for (int j = 1; j <= maxv; j++)
            {
                fs.add((1000.0f * j)/(float)x);
            }
        }
        float optt = (float)t / m;

        fs.sort(Comparator.comparingDouble(f -> f));
        int fc = n;
        for (float f : fs) {
            float t2 = fc / f;
            optt = Math.min(optt, t2);
            fc++;
        }

        System.out.println(optt);
    }
}