fn main() {
    let mut nk = String::new();
    std::io::stdin().read_line(&mut nk).ok();
    let nk: Vec<usize> = nk.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nk[0];
    let k = nk[1];

    let size = (n / k + if n % k > 0 { 1 } else { 0 }).max((n as f64).sqrt().ceil() as usize);
    println!("{}", size);
    let mut grid = vec![vec!["."; size]; size];
    let mut cnt = 0usize;
    for i in 0..size {
        for j in 0..k.min(size) {
            grid[i][(i+j)%size] = "#";
            cnt += 1;
            if cnt == n { break; }
        }
        if cnt == n { break; }
    }
    for i in 0..size {
        println!("{}", grid[i].join(""));
    }
}