#include <bits/stdc++.h>
using namespace std;
int main() {
  char s[100];
  int n, t;
  cin >> n >> t;
  if (n == 1 && t == 10)
    cout << -1;
  else {
    if (t < 10)
      s[0] = t + 48;
    else
      s[0] = '1';
    for (int i = 1; i < n; i++) {
      s[i] = '0';
    }
    for (int i = 0; i < n; i++) {
      cout << s[i];
    }
  }
}
