using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("81");
            //315
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("216");
            //858
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("10000000000");
            //30756925116342
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static long[] GetSplitArr(string pStr)
    {
        return (pStr == "" ? new string[0] : pStr.Split(' ')).Select(pX => long.Parse(pX)).ToArray();
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        long N = long.Parse(  InputList[0]);

        long Jyougen = 1;
        for (long I = 1; I * I <= N; I++) {
            Jyougen = I;
        }
        Eratosthenes(Jyougen);

        long Answer = 0;
        foreach (long EachSosuu in mSosuuArr) {
            long CurrVal = EachSosuu * EachSosuu;
            while (true) {
                if (CurrVal <= N) {
                    Answer += CurrVal;
                }
                else {
                    break;
                }
                CurrVal *= EachSosuu;
            }
        }
        Console.WriteLine(Answer);
    }

    static long[] mSosuuArr;

    // エラトステネスの篩
    static void Eratosthenes(long pJyougen)
    {
        bool[] IsSosuuArr = new bool[pJyougen + 1];
        for (int I = 2; I <= IsSosuuArr.GetUpperBound(0); I++) {
            IsSosuuArr[I] = true;
        }
        for (int I = 2; I * I <= IsSosuuArr.GetUpperBound(0); I++) {
            if (IsSosuuArr[I]) {
                for (int J = I * 2; J <= IsSosuuArr.GetUpperBound(0); J += I) {
                    IsSosuuArr[J] = false;
                }
            }
        }

        var SosuuList = new List<long>();
        for (int I = 2; I <= IsSosuuArr.GetUpperBound(0); I++) {
            if (IsSosuuArr[I]) SosuuList.Add(I);
        }

        mSosuuArr = SosuuList.ToArray();
    }
}