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: Wrong Answer)

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

namespace C
{
    public class Program
    {
        static void Main(string[] args)
        {
            var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);
            Solve();
            Console.Out.Flush();
        }

        public static void Solve()
        {
            var N = long.Parse(Console.ReadLine());
            var answer = "";
            while (N > 0)
            {
                var div = N / 26L;
                var mod = N % 26L;
                answer += GetCharString(mod);
                N = div;
            }
            Console.WriteLine(string.Join("", answer.Reverse()));
        }

        public static string GetCharString(long num)
        {
            var ret = "";
            switch (num)
            {
                case 1: ret = "a"; break;
                case 2: ret = "b"; break;
                case 3: ret = "c"; break;
                case 4: ret = "d"; break;
                case 5: ret = "e"; break;
                case 6: ret = "f"; break;
                case 7: ret = "g"; break;
                case 8: ret = "h"; break;
                case 9: ret = "i"; break;
                case 10: ret = "j"; break;
                case 11: ret = "k"; break;
                case 12: ret = "l"; break;
                case 13: ret = "m"; break;
                case 14: ret = "n"; break;
                case 15: ret = "o"; break;
                case 16: ret = "p"; break;
                case 17: ret = "q"; break;
                case 18: ret = "r"; break;
                case 19: ret = "s"; break;
                case 20: ret = "t"; break;
                case 21: ret = "u"; break;
                case 22: ret = "v"; break;
                case 23: ret = "w"; break;
                case 24: ret = "x"; break;
                case 26: ret = "y"; break;
                case 0: ret = "z"; break;
            }
            return ret;
        }
    }
}