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