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: Accepted)

#include <stdio.h>

int main(void){

    long long int n;
    scanf("%lld",&n);
    
    int revAns[15];
    int revAnsNum=0;
    long long int keta=1;
    long long int minus=0;
    
    while(((n-minus)/keta)>=0){
    revAns[revAnsNum]=((((n-minus-1)/keta))%26);
    revAnsNum++;
    keta*=26;
    minus+=keta;
    //printf("%d %lld %lld %lld %lld\n",revAnsNum,keta,minus,n,(n-minus)/keta);
    }
    
    //printf("%d ",revAnsNum);
    
    for(int i = revAnsNum-2;i>=0;i--){
        printf("%c",97+revAns[i]);
    }
    
    
    
    /*while(n>0){
    
    i=n%26;
    n/=26;
    printf("%d ",i);
    }*/
 
 

 return 0;
}