namespace AtCoder;

#nullable enable

using System.Numerics;

static class Extensions
{
    public static T[] Repeat<T>(this int time, Func<T> F) => Enumerable.Range(0, time).Select(_ => F()).ToArray();
}

class AtCoder
{
    object? Solve()
    {
        var n = Int();
        var h = Int();
        var az = n.Repeat(Int);
        var bz = n.Repeat(Int);
        var ans = 0L;
        var av = 0L;
        var ah = 0L;
        var sh = 0L;
        var r = 0;
        for (var l = 0; l < n; l++)
        {
            while (r < n)
            {
                long w = r - l + 1;
                if (w * bz[r] + ah <= h)
                {
                    ah += w * bz[r];
                    sh += bz[r];
                    av += az[r];
                    r++;
                    continue;
                }
                break;
            }
            ans = Math.Max(ans, av);
            av -= az[l];
            ah -= sh;
            sh -= bz[l];
        }
        return ans;
    }

    public static void Main() => new AtCoder().Run();
    public void Run()
    {
        var res = Solve();
        if (res != null)
        {
            if (res is bool yes) res = yes ? "Yes" : "No";
            sw.WriteLine(res);
        }
        sw.Flush();
    }

    string[] input = Array.Empty<string>();
    int iter = 0;
    readonly StreamWriter sw = new(Console.OpenStandardOutput()) { AutoFlush = false };

    #pragma warning disable IDE0051
    string String()
    {
        while (iter >= input.Length) (input, iter) = (Console.ReadLine()!.Split(' '), 0);
        return input[iter++];
    }
    T Input<T>() where T : IParsable<T> => T.Parse(String(), null);
    int Int() => Input<int>();
    void Out(object? x, string? separator = null)
    {
        separator ??= Environment.NewLine;
        if (x is System.Collections.IEnumerable obj and not string)
        {
            var firstLine = true;
            foreach (var item in obj)
            {
                if (!firstLine) sw.Write(separator);
                firstLine = false;
                sw.Write(item);
            }
        }
        else sw.Write(x);
        sw.WriteLine();
    }
    #pragma warning restore IDE0051
}