#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, t;
  cin >> n >> t;
  if (n == 1) {
    if (t < 10)
      cout << t;
    else
      cout << -1;
    return 0;
  }
  vector<int> ans(n, 0);
  ans[0] = 1;
  int rest = 0;
  for (int x : ans) {
    rest = rest * 10 + x;
    rest %= t;
  }
  if (rest) ans.back() += t - rest;
  for (int x : ans) cout << x;
}
