use std::io::*;
use std::str::FromStr;
use utils::*;

pub fn main() {
    let i = stdin();
    let mut o = Vec::new();
    run(i.lock(), &mut o);
    stdout().write_all(&o).unwrap();
}

fn run<R: BufRead, W: Write>(i: R, o: &mut W) {
    let mut i = CpReader::new(i);
    let n = i.read::<usize>();
    for s in solve(n) {
        writeln!(o, "{}", s).unwrap();
    }
}
fn solve(n: usize) -> Vec<String> {
    let mut ss = Vec::new();
    for i in 0..n {
        let mut s = String::new();
        s += "a";
        let mut j = i;
        while j != 0 {
            s.push((b'a' + (j % 26) as u8) as char);
            j /= 26;
        }
        if i == n - 1 {
            s += "n";
        } else {
            s += "a";
        }
        ss.push(s);
    }
    ss
}

mod utils {
    use super::*;

    pub struct CpReader<R: BufRead> {
        r: R,
        s: String,
    }

    impl<R: BufRead> CpReader<R> {
        pub fn new(r: R) -> Self {
            CpReader {
                r: r,
                s: String::new(),
            }
        }
        pub fn read_line(&mut self) -> &str {
            self.s.clear();
            self.r.read_line(&mut self.s).unwrap();
            self.s.trim()
        }

        pub fn read<T: FromStr>(&mut self) -> T {
            self.read_line().parse().ok().unwrap()
        }
    }
}