Problem:
Score : 300 points

Problem Statement

1000000000000001 dogs suddenly appeared under the roof of Roger's house, all of which he decided to keep. The dogs had been numbered 1 through 1000000000000001, but he gave them new names, as follows:

the dogs numbered 1,2,\cdots,26 were respectively given the names a, b, ..., z;

the dogs numbered 27,28,29,\cdots,701,702 were respectively given the names aa, ab, ac, ..., zy, zz;

the dogs numbered 703,704,705,\cdots,18277,18278 were respectively given the names aaa, aab, aac, ..., zzy, zzz;

the dogs numbered 18279,18280,18281,\cdots,475253,475254 were respectively given the names aaaa, aaab, aaac, ..., zzzy, zzzz;

the dogs numbered 475255,475256,\cdots were respectively given the names aaaaa, aaaab, ...;

and so on.

To sum it up, the dogs numbered 1, 2, \cdots were respectively given the following names:

a, b, ..., z, aa, ab, ..., az, ba, bb, ..., bz, ..., za, zb, ..., zz, aaa, aab, ..., aaz, aba, abb, ..., abz, ..., zzz, aaaa, ...

Now, Roger asks you:

"What is the name for the dog numbered N?"

Constraints

N is an integer.

1 \leq N \leq 1000000000000001

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer to Roger's question as a string consisting of lowercase English letters.

Sample Input 1

2

Sample Output 1

b

Sample Input 2

27

Sample Output 2

aa

Sample Input 3

123456789

Sample Output 3

jjddja

Solution in C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;

class Program
{
    static void Main(string[] args)
    {
        var n = ReadLong();
        var alphabets = "abcdefghijklmnopqrstuvwxyz";
        var result = "";
        while (n > 0)
        {
            n -= 1;
            var a = (int) (n % 26);
            n /= 26;

            var c = alphabets[a];
            result = c + result;
        }

        Console.WriteLine(result);
    }


    private static string Read() => Console.ReadLine();
    private static char[] ReadChars() => Array.ConvertAll(Read().Split(), a => a[0]);
    private static int ReadInt() => int.Parse(Read());
    private static long ReadLong() => long.Parse(Read());
    private static double ReadDouble() => double.Parse(Read());
    private static int[] ReadInts() => Array.ConvertAll(Read().Split(), int.Parse);
    private static long[] ReadLongs() => Array.ConvertAll(Read().Split(), long.Parse);
    private static double[] ReadDoubles() => Array.ConvertAll(Read().Split(), double.Parse);
}