#include <bits/stdc++.h>
using namespace std;
const int oo = 0x3f3f3f3f;
const double PI = 2 * acos(0.0);
const int Numnodes = ((int)1e5) + 3;
int main() {
  int N, K;
  cin >> N >> K;
  if (K == 10) {
    if (N == 1) return cout << -1 << endl, 0;
    for (long long int i = 0; i < (N - 1); i++) cout << 1;
    cout << 0;
  } else
    for (long long int i = 0; i < (N); i++) cout << K;
}
