#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  int n, d;
  cin >> n >> d;
  if (n == 1 && d == 10) {
    cout << -1;
  } else {
    (d < 10) ? cout << d : cout << 1;
    for (int i = 0; i < n - 1; i++) {
      cout << 0;
    }
  }
  cout << endl;
  return 0;
}
