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 (GCC 9.2.1) (judge verdict: Wrong Answer)

    #include <stdio.h>
    #include <math.h>
    
    void f(long long int n)
    {
        if (n <= 26)
        {
    
                n = n % 26;
        if (!n)
        n = 26;
            printf("%c", 'a' + n);
            return;
        }
        f (n / 26);
        n = n % 26;
        if (!n)
        n = 26;
        printf("%c", 'a' + n);
    }
    
    
    int main(void){
        long long int i, n, x, y, a, b, tmp;
        scanf("%lld", &n);

        a = 1;
        while (1){
        if (pow(26, a) < n)
            n-=pow(26,a);
        else
            break;
            a++;
        }
                if (n == 1)
        {
            for (i = 0; i < a; i++)
            printf("a");
            return (0);
        }
        f(n - 1); 
    }