use proconio::{input, marker::Chars};

fn main() {
    input! {
        n: usize, m: usize,
        mut s: [Chars; n],
    }

    for _ in 0..2 {
        s = transpose(s);
        s.iter_mut().for_each(|row| row.sort_unstable());
    }

    for row in &s {
        println!("{}", row.iter().collect::<String>());
    }
}

fn transpose(s: Vec<Vec<char>>) -> Vec<Vec<char>> {
    let h = s.len();
    let w = s[0].len();
    let mut res = vec![vec!['.'; h]; w];
    for i in 0..w {
        for j in 0..h {
            res[i][j] = s[j][i];
        }
    }
    res
}