#include <bits/stdc++.h>
using namespace std;
double pi = 3.1415926536;
const int oo = (int)1e9;
int dx[] = {0, 1, 0, -1};
int dy[] = {1, 0, -1, 0};
int di[] = {0, 0, 1, -1, 1, 1, -1, -1};
int dj[] = {1, -1, 0, 0, 1, -1, 1, -1};
int arr[1000001];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m;
  cin >> n >> m;
  bool check = true;
  string s;
  int counter = 0;
  while (n--) {
    if (check && m >= 2)
      s += "101", m -= 2, check = false;
    else if (m && !check)
      s += "01", m -= 1;
    else if (!n)
      s += '0';
    else
      counter++;
  }
  check = true;
  if (counter > 1) check = false;
  if (m < 0) {
    check = false;
  }
  bool enter = true;
  string final_answer;
  if (counter) final_answer += '0';
  for (int i = 0; i < ((int)(s).size()); i++) {
    if (m && enter) final_answer += '1', m--, enter = false;
    final_answer += s[i];
    if (s[i] == '0') enter = true;
  }
  if (m > 0) check = false;
  if (!check) {
    cout << -1;
  } else
    cout << final_answer;
}
