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 Rust (1.42.0) (judge verdict: Runtime Error)

#![allow(unused_imports)]
// use itertools::Itertools;
use proconio::{input, marker::*};

fn main() {
    input! {
        mut n: usize
    };
    let alphabet = (b'a'..=b'z').map(|c| c as char).collect::<Vec<_>>();
    //   26**10 = 141167095653376
    //          < 1000000000000001
    // < 26**11 = 3670344486987776
    // (1..10).map{|i| 26**i}.reverse
    let arr = [141167095653376, 5429503678976, 208827064576, 8031810176, 308915776, 11881376, 456976, 17576, 676, 26];
    let vv: Vec<usize> = arr.iter().map(|i| {
        n %= i * 26;
        (n - 1) / i
    }).collect();
    let mut s = "".to_string();
    dbg!(&vv);
    for v in vv {
        if v > 0 {
            s.push(alphabet[v - 1]);
        }
    }
    s.push(alphabet[(n - 1) % 26]);
    println!("{}", s);
}