#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, t;
  cin >> n >> t;
  if (t == 10) {
    if (n < 2) {
      cout << "-1\n";
      return 0;
    }
    cout << 1;
    for (int i = 0; i < n - 1; i++) cout << 0;
    cout << "\n";
    return 0;
  }
  cout << t;
  for (int i = 0; i < n - 1; i++) cout << 0;
  cout << "\n";
  return 0;
}
