use std::io::{Read, stdin};

fn main() {
    let mut buf = String::new();
    stdin().read_to_string(&mut buf).unwrap();
    let mut tok = buf.split_whitespace();
    let mut get = || tok.next().unwrap();
    macro_rules! get {
        ($t:ty) => (get().parse::<$t>().unwrap());
        () => (get!(i64));
    }
    
    let n = get!(u32);
    let mut ans = String::new();
    let mut last = 'a';
    for i in 0..n {
        ans.push(last);
        let mut x = i + 1;
        while x > 0 {
            let c = x % 26 + 'a' as u32;
            let c = c as u8 as char;
            ans.push(c);
            last = c;
            x /= 26;
        }
        ans.push('\n');
    }
    print!("{}", ans);
}