using System;

public class Hello
{
    static void Main()
    {
        var n = long.Parse(Console.ReadLine().Trim());
        getAns(n);
    }
    static void getAns(long n)
    {
        if (n < 3) { Console.WriteLine(n); return; }
        var ans = (n - 3) * 5L + 3;
        Console.WriteLine(ans);
    }
}