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>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)
using ll = long long;
using P = pair<int, int>;

char toalpha(int x) {
    char ans;
    if (x == 1) ans = 'a';
    if (x == 2) ans = 'b';
    if (x == 3) ans = 'c';
    if (x == 4) ans = 'd';
    if (x == 5) ans = 'e';
    if (x == 6) ans = 'f';
    if (x == 7) ans = 'g';
    if (x == 8) ans = 'h';
    if (x == 9) ans = 'i';
    if (x == 10) ans = 'j';
    if (x == 11) ans = 'k';
    if (x == 12) ans = 'l';
    if (x == 13) ans = 'm';
    if (x == 14) ans = 'n';
    if (x == 15) ans = 'o';
    if (x == 16) ans = 'p';
    if (x == 17) ans = 'q';
    if (x == 18) ans = 'r';
    if (x == 19) ans = 's';
    if (x == 20) ans = 't';
    if (x == 21) ans = 'u';
    if (x == 22) ans = 'v';
    if (x == 23) ans = 'w';
    if (x == 24) ans = 'x';
    if (x == 25) ans = 'y';
    if (x == 0) ans = 'z';

    return ans;
}

int main() {
    ll n;
    cin >> n;

    string ans = "";

    while(n) {
        int amari = n%26;
        n /= 26;
        ans += toalpha(amari);
    }
    reverse(ans.begin(), ans.end());
    cout << ans << endl;

    return 0;
}