#include <bits/stdc++.h>
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long lcm(long long a, long long b) { return a * b / gcd(a, b); }
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t;
  t = 1;
  while (t--) {
    long long n, m;
    cin >> n >> m;
    if (m < n - 1 || m > 2 * (n + 1))
      cout << -1;
    else {
      if (m == n - 1) {
        for (long long i = 0; i < m; i++) cout << "01";
        cout << "0";
        return 0;
      }
      if (m == n) {
        for (long long i = 0; i < m; i++) cout << "10";
        return 0;
      }
      long long rem = m % (n + 1), ab = n - rem;
      if (rem == 0 && m / (n + 1) == 2) rem = n, ab = 0;
      long long c = m - rem * 2 - ab * 1;
      while (rem--) cout << "110";
      while (ab--) cout << "10";
      for (long long i = 0; i < c; i++) cout << "1";
    }
  }
  cerr << "Time taken : " << (double)clock() / CLOCKS_PER_SEC << " secs"
       << endl;
  return 0;
}
