#include <bits/stdc++.h>

using namespace std;


long long n, m, t, a[3000001], k;


int main()

{
    scanf("%d%d", &n, &m);
    if (n - 1 <= m && m <= 2*(n + 1))
    {
        if (m == n - 1) {
            a[0] = -1;
            a[m + 1] = -1;
            t = n - 1;
        }
        else if (m == n)
        {
            a[m + 1] = -1;
            t = n;
        }
        else t = n + 1;
        k = m % t;
        if (k == 0 && m != t) k = n + 1;
        if (a[0] == -1) cout<<"0";
        for (int i = 1; i <= n; i++)
        {
            if (a[i] != -1){
            if (k > 0) cout<<"110";
            else cout<<"10";
            k--;
            }
        }
        if (a[m + 1] != -1) {
            if (k > 0) cout<<"11"<<endl;
            else cout<<"1"<<endl;
        }
    }
    else cout<<"-1"<<endl;
}