#include <bits/stdc++.h>
using namespace std;
int n, t, i = 1;
string x, res;
string toStr(int x) {
  string ans = "";
  while (x) {
    ans += ((x % 10) + '0');
    x /= 10;
  }
  reverse(ans.begin(), ans.end());
  return ans;
}
int main() {
  cin >> n >> t;
  x = toStr(t);
  if (x.length() > n) {
    cout << -1;
    return 0;
  }
  res = x;
  for (int i = 0; i < n - x.length(); i++) {
    res += '0';
  }
  cout << res;
}
