#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, count = 0;
  cin >> n >> m;
  string a;
  while (m) {
    count++;
    a += (m % 10) + 48;
    m /= 10;
  }
  reverse(a.begin(), a.end());
  if (n < count) {
    cout << "-1" << endl;
    return 0;
  }
  n -= count;
  while (n--) {
    a += "0";
  }
  cout << a << endl;
  return 0;
}
