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: Accepted)

use proconio::input;

fn main() {
    input! {
        mut n: u128
    }

    solve(n);
}

fn solve(mut n: u128) {
    let mut ans: Vec<char> = vec![];
    while n > 0 {
        n -= 1;
        let x = to_char((n % 26) as u32);
        ans.push(x);
        n /= 26;
    }
    ans.reverse();

    for c in ans {
        print!("{}", c);
    }
    println!("");
}

fn to_char(num: u32) -> char {
    match num {
        0 => 'a',
        1 => 'b',
        2 => 'c',
        3 => 'd',
        4 => 'e',
        5 => 'f',
        6 => 'g',
        7 => 'h',
        8 => 'i',
        9 => 'j',
        10 => 'k',
        11 => 'l',
        12 => 'm',
        13 => 'n',
        14 => 'o',
        15 => 'p',
        16 => 'q',
        17 => 'r',
        18 => 's',
        19 => 't',
        20 => 'u',
        21 => 'v',
        22 => 'w',
        23 => 'x',
        24 => 'y',
        _ => 'z',
    }
}