mod io {
    #[macro_export]
    macro_rules! parse {
        ($b:expr, [u8]) => ($b);
        ($b:expr, String) => ($b.into_iter().map(|b| b as char).collect::<String>());
        ($b:expr, $t:ty) => (parse!($b, String).parse::<$t>().unwrap());
    }

    #[macro_export]
    macro_rules! scan {
        ($r:expr, [$t:tt; $n:expr]) => ((0..$n).map(|_| scan!($r, $t)).collect::<Vec<_>>());
        ($r:expr, ($($t:tt),*)) => (($(scan!($r, $t)),*));
        ($r:expr, $t:tt) => (parse!(io::scan($r), $t));
    }

    use std::io::{BufRead, ErrorKind};

    pub fn scan<R: BufRead>(r: &mut R) -> Vec<u8> {
        let mut buf = Vec::new();
        loop {
            let (done, used) = {
                let available = match r.fill_buf() {
                    Ok(n) => n,
                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
                    Err(e) => panic!(e), 
                };
                match available.iter().position(u8::is_ascii_whitespace) {
                    Some(i) => {
                        buf.extend_from_slice(&available[..i]);
                        (buf.len() > 0, i + 1)
                    }
                    None => {
                        buf.extend_from_slice(available);
                        (false, available.len())
                    }
                }
            };
            r.consume(used);
            if done || used == 0 {
                return buf;
            }
        }
    }
}

use std::io::{BufRead, Write};

fn run<R: BufRead, W: Write>(reader: &mut R, writer: &mut W) {
    let (n, k) = scan!(reader, (usize, usize));

    if k <= 3 {
        if n >= 9 {
            writer.write_all(b"-1\n").ok();
            return;
        }

        for s in 0..(1 << n) {
            let mut max = 1;
            for i in 0..n {
                'j: for j in (i + k - 1)..n {
                    let (mut l, mut r) = (i, j);
                    while l < r {
                        if s >> l & 1 != s >> r & 1 {
                            continue 'j;
                        }
                        l += 1;
                        r -= 1;
                    }
                    max = max.max(j - i + 1);
                }
            }
            if max == k {
                writeln!(writer, "{:0>1$b}", s, n).ok();
                return;
            }
        }
        writer.write_all(b"-1\n").ok();
    } else {
        let before = (b"1").iter().cycle().take(k);
        let after = (b"010011").iter().cycle().take(n - k);
        let ans = before.chain(after).chain(b"\n").cloned().collect::<Vec<_>>();
        writer.write_all(&ans).ok();    
    }
}

fn main() {
    let (stdin, stdout) = (std::io::stdin(), std::io::stdout());
    let mut reader = std::io::BufReader::new(stdin.lock());
    let mut writer = std::io::BufWriter::new(stdout.lock());
    run(&mut reader, &mut writer);
}