#include <bits/stdc++.h>
using std::cerr;
using std::cin;
using std::cout;
using std::ios_base;
using std::log10;
using std::trunc;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int n, t;
  cin >> n >> t;
  if (n == 1 and t == 10) {
    cout << "-1"
         << "\n";
    return 0;
  }
  int digit = t % 10, ans[n];
  ans[n - 1] = digit;
  for (int i = n - 2; ~i; --i) ans[i] = digit == 0 ? 1 : digit;
  for (int i = 0; i < n; i++) cout << ans[i];
  cout << "\n";
  return 0;
}
