#include <bits/stdc++.h>
using namespace std;
void online_judge() {}
void ISO() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
}
long long binpow(long long a, long long b, long long m) {
  a %= m;
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a % m;
    a = a * a % m;
    b >>= 1;
  }
  return res;
}
int main() {
  ISO();
  online_judge();
  long long n, m;
  cin >> m >> n;
  if (n < m - 1) {
    cout << -1 << "\n";
    return 0;
  }
  string s;
  n -= (m - 1);
  for (long long i = 1; i < m; ++i) {
    s += "01";
  }
  s += "0";
  long long cnt = 1;
  while (n - 1 >= 0 && cnt <= 2) {
    s = "1" + s;
    cnt++;
    n--;
  }
  cnt = 1;
  while (n - 1 >= 0 && cnt <= 2) {
    s += "1";
    cnt++;
    n--;
  }
  if (n - (m - 1) <= 0) {
    for (long long i = 0; i < s.length(); ++i) {
      if (s[i] == '0' && n) {
        cout << "01";
        n -= 1;
      } else {
        cout << s[i];
      }
    }
  } else {
    cout << -1 << "\n";
    return 0;
  }
  cerr << "Time elapsed: " << clock() / 1000 << " ms" << endl;
  return 0;
}
