using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var n = int.Parse(line[0]);
        var m = int.Parse(line[1]);
        line = Console.ReadLine().Trim().Split(' ');
        var a = Array.ConvertAll(line, int.Parse);
        getAns(n, m, a);
    }
    static void getAns(int n, int m, int[] a)
    {
        long pre = a[0];
        long ans = pre;
        var p = 2;
        for (int i = 1; i < n; i++)
        {
            var t = pre + a[i];
            ans = Min(ans, t / p++);
            pre = t;
        }
        Console.WriteLine(ans / m);
    }
}