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 <bits/stdc++.h>
#include <string>
#include <algorithm>
#include <vector>
#include <stack>
using namespace std;
typedef long long ll;
stack<string> sta;

int main(){
    ll n; cin >> n;
    ll i = 0;
    while(n>0){
        ll d = n % 26;
        string c ;
        if(d==1){c = 'a';}
        if(d==2){c = 'b';}
        if(d==3){c = 'c';}
        if(d==4){c = 'd';}
        if(d==5){c = 'e';}
        if(d==6){c = 'f';}
        if(d==7){c = 'g';}
        if(d==8){c = 'h';}
        if(d==9){c = 'i';}
        if(d==10){c = 'j';}
        if(d==11){c = 'k';}
        if(d==12){c = 'l';}
        if(d==13){c = 'm';}
        if(d==14){c = 'n';}
        if(d==15){c = 'o';}
        if(d==16){c = 'p';}
        if(d==17){c = 'q';}
        if(d==18){c = 'r';}
        if(d==19){c = 's';}
        if(d==20){c = 't';}
        if(d==21){c = 'u';}
        if(d==22){c = 'v';}
        if(d==23){c = 'w';}
        if(d==24){c = 'x';}
        if(d==25){c = 'y';}
        if(d==26){c = 'z';}
        sta.push(c);
        n /= 26;
        ++i;
    }
    while(!sta.empty()){
        cout << sta.top(); sta.pop();
    }
    return 0;
}