#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  long long n, t;
  cin >> n >> t;
  string s = string(n, char(48 + t));
  if (t == 10 && n != 1) {
    s = string(n - 1, '1') + "0";
  } else if (t == 10 && n == 1)
    s = "-1";
  cout << s << "\n";
  return 0;
}
