#![allow(non_snake_case)]
#![allow(unused_imports)]
//use itertools::Itertools;
//use proconio::input;
//use proconio::marker::*;
use std::cmp::Reverse;
use std::collections::*;

fn main() {
    input! {
        n:usize,
        k:usize,
    }

    if n < 9 {
        let ans = solve(n, k);
        if let Some(ans) = ans {
            for i in (0..n).rev() {
                print!("{}", (ans >> i) & 1);
            }
            println!()
        } else {
            println!("-1");
        }
    } else if k < 4 {
        println!("-1");
    } else {
        let mut ans = vec![];
        for _ in 0..k {
            ans.push(1);
        }

        let s = [0, 1, 0, 0, 1, 1];
        for i in 0..n - k {
            ans.push(s[i % 6]);
        }

        for i in 0..n {
            print!("{}", ans[i]);
        }
        println!();
    }
}

fn solve(n: usize, k: usize) -> Option<usize> {
    for s in 0..1 << n {
        let mut max = 0;
        for i in 0..n {
            for j in i + 1..=n {
                if (i..j)
                    .zip((i..j).rev())
                    .all(|(k, l)| (s & (1 << k) != 0) == (s & (1 << l) != 0))
                {
                    max = max.max(j - i);
                }
            }
        }
        if max == k {
            return Some(s);
        }
    }
    None
}
mod input {
    #[macro_export]
    macro_rules! input {
        (source = $s:expr, $($r:tt)*) => {
            let mut iter = $s.split_whitespace();
            input_inner!{iter, $($r)*}
        };
        ($($r:tt)*) => {
            let s = {
                use std::io::Read;
                let mut s = String::new();
                std::io::stdin().read_to_string(&mut s).unwrap();
                s
            };
            let mut iter = s.split_whitespace();
            input_inner!{iter, $($r)*}
        };
    }

    #[macro_export]
    macro_rules! input_inner {
        ($iter:expr) => {};
        ($iter:expr, ) => {};

        ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
            let $var = read_value!($iter, $t);
            input_inner!{$iter $($r)*}
        };
    }

    #[macro_export]
    macro_rules! read_value {
        ($iter:expr, ( $($t:tt),* )) => {
            ( $(read_value!($iter, $t)),* )
        };

        ($iter:expr, [ $t:tt ; $len:expr ]) => {
            (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
        };

        ($iter:expr, chars) => {
            read_value!($iter, String).chars().collect::<Vec<char>>()
        };

        ($iter:expr, usize1) => {
            read_value!($iter, usize) - 1
        };

        ($iter:expr, $t:ty) => {
            $iter.next().unwrap().parse::<$t>().expect("Parse error")
        };
    }
}