using System;
using System.Linq;
using System.Collections.Generic;
using System.IO;
using System.Diagnostics;

class Program{
    static void Main(){
        var watch = new Stopwatch();
        TextReader reader;
        string filename = "";
        if(filename.Length!=0)reader = new StreamReader(filename);
        else reader = Console.In;
        var n = Int64.Parse(reader.ReadLine());
        long[] lis = reader.ReadLine().Split().Select(Int64.Parse).ToArray();
        var k = Int64.Parse(reader.ReadLine());

        watch.Start();
        double left = 0;
        double right = 10e9;
        /*誤差の吸収がめんどくさいので回数決め打ちループ */
        int cnt = 0;
        while(left<right && cnt<100){
            var mid = (left+right)/2;
            var v = Func(mid, lis, n);
            if(v > k) left = mid;
            else right = mid; 
            cnt++;
        }
        Console.WriteLine(right);
    }

    static long Func(double p, long[] lis, long n){
        long ans = 0;
        for(long i=0; i<n; i++){
            ans+=(long)((double)lis[i]/p);
        }
        return ans;
    }
}