#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>

int main(){
    int n, m;
    std::cin >> n >> m;
    std::vector<float> fs;
    int x;
    long long t = 0;
    for (int i = 0; i < n; i++)
    {
        std::cin >> x;
        t += (m * x) / 1000 + ((m * x) % 1000 == 0 ? 0 : 1);
        int maxv = (m * x) / 1000;
        for (int i = 1; i <= maxv; i++)
        {
            fs.push_back((1000.0f * i)/(float)x);
        }
    }
    float optt = (float)t / m;

    std::sort(fs.begin(), fs.end());
    int fc = n;
    for (int i = 0; i < fs.size(); i++)
    {
        float t = fc / fs[i];
        optt = std::min(optt, t);
        fc++;
    }

    std::cout << std::setprecision(10) << optt << std::endl;

}