using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using Enu = System.Linq.Enumerable;

class Program
{
    void Solve()
    {
        int N = reader.Int(), V = reader.Int();
        long[] A = reader.IntArray(N).Select(a => (long)a).ToArray();
        long[] Sum = Enu.Range(1, N).Select(i => A.Take(i).Sum()).ToArray();
        long ans = Sum[N - 1];
        V -= N;

        while (V > 0)
        {
            int best = -1;
            double bestAvg = double.MaxValue;
            for (int i = 0; i < N && i + 1 <= V; i++)
            {
                double avg = (double)Sum[i] / (i + 1);
                if (avg < bestAvg)
                {
                    bestAvg = avg;
                    best = i;
                }
            }
            int mult = V / (best + 1);
            V -= mult * (best + 1);
            ans += Sum[best] * mult;
        }

        Console.WriteLine(ans);
    }




    Reader reader = new Reader(Console.In);
    static void Main()
    {
        new Program().Solve();
    }
}

class Reader
{
    private readonly TextReader reader;
    private readonly char[] separator = { ' ' };
    private readonly StringSplitOptions removeOp = StringSplitOptions.RemoveEmptyEntries;
    private string[] A = new string[0];
    private int i;

    public Reader(TextReader r) { reader = r; }
    public Reader(string file) { reader = new StreamReader(file); }
    public bool HasNext() { return Enqueue(); }
    public string String() { return Dequeue(); }
    public int Int() { return int.Parse(Dequeue()); }
    public long Long() { return long.Parse(Dequeue()); }
    public double Double() { return double.Parse(Dequeue()); }
    public int[] IntLine() { var s = Line(); return s == "" ? new int[0] : Array.ConvertAll(Split(s), int.Parse); }
    public int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public int[][] IntGrid(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); }
    public string Line() { return reader.ReadLine().Trim(); }
    private string[] Split(string s) { return s.Split(separator, removeOp); }
    private bool Enqueue()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return Enqueue();
        A = Split(line);
        i = 0;
        return true;
    }
    private string Dequeue() { Enqueue(); return A[i++]; }
}