#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n >> m;
  string s = "";
  if (n <= m) {
    vector<char> fin((3 * n) + 7, '-1');
    for (int i = 0; i < 3 * n; i += 3) {
      fin[i] = '1';
      fin[i + 1] = '_';
      fin[i + 2] = '0';
      m--;
    }
    int index = 1;
    for (int i = 0; i < m; i++) {
      fin[index] = '1';
      index += 3;
      if (index >= 3 * n) {
        if (m - i - 1 > 2) {
          cout << "-1" << endl;
          return 0;
        }
        if (m - i - 1 == 2) {
          for (int i = 0; i < 3 * n; i++) {
            if (fin[i] != '-1' && fin[i] != '_') {
              cout << fin[i];
            }
          }
          cout << "11" << endl;
          return 0;
        }
        if (m - i - 1 == 1) {
          for (int i = 0; i < 3 * n; i++) {
            if (fin[i] != '-1' && fin[i] != '_') {
              cout << fin[i];
            }
          }
          cout << "1" << endl;
          return 0;
        }
      }
    }
    for (int i = 0; i < 3 * n; i++) {
      if (fin[i] != '-1' && fin[i] != '_') {
        cout << fin[i];
      }
    }
    cout << endl;
    return 0;
  } else {
    for (int i = 0; i < m; i++) {
      s += "0";
      s += "1";
      n--;
    }
    if (n == 1) {
      s += "0";
      cout << s << endl;
      return 0;
    } else {
      cout << "-1" << endl;
      return 0;
    }
  }
}
