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
{
    static readonly long INF = (long)1e18;

    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();
        if (V <= N) { Console.WriteLine(Sum[N - 1]); return; }
        V -= N;

        int best = 0; // [0, best]
        for (int i = 1; i < N; i++)
            if (Sum[i] * (best + 1) < Sum[best] * (i + 1))
                best = i;
        var dp = new long[N * N + 1];
        for (int i = 1; i < dp.Length; i++) dp[i] = INF;
        for (int i = 0; i < N; i++)
            if (i != best)
                for (long prev = 0; prev + i + 1 < dp.Length; prev++)
                    dp[prev + i + 1] = Math.Min(dp[prev + i + 1], dp[prev] + Sum[i]);
        long min = INF;
        for (int i = 0; i < dp.Length; i++)
            if ((V - i) % (best + 1) == 0)
                min = Math.Min(min, dp[i] + (V - i) / (best + 1) * Sum[best]);
        min += Sum[N - 1];

        Console.WriteLine(min);
    }




    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++]; }
}