#include <bits/stdc++.h>
using namespace std;
const int maxxn = 1e5 + 12, inf = 1e9;
int n, t;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> t;
  if (t == 10 && n > 1) {
    cout << 1;
    for (int i = 0; i < n - 1; i++) cout << 0;
  } else if (t != 10) {
    for (int i = 0; i < n; i++) cout << t;
  } else
    cout << -1;
  cout << endl;
  return 0;
}
