using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, k) = (c[0], c[1]);
        WriteLine(LPS(n, k));
    }
    static string LPS(int n, int k)
    {
        if (k == 1)
        {
            if (n == 1) return "0";
        }
        else if (k == 2)
        {
            if (n <= 4) return "0011"[0..n];
        }
        else if (k == 3)
        {
            if (n < 8) return "00010111"[0..n];
        }
        else
        {
            var ans = new char[n];
            for (var i = 0; i < k; ++i) ans[i] = '1';
            for (var i = k; i < n; ++i) ans[i] = "001101"[(i - k) % 6];
            return string.Concat(ans);
        }
        return "-1";
    }
}