#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
using namespace std;
long long MOD = 998244353;
double eps = 1e-12;
void solve() {
  long long n, k;
  cin >> n >> k;
  if (n == 1 && k == 10) {
    cout << "-1"
         << "\n";
    return;
  }
  if (k == 10) {
    cout << 1;
    for (int i = 1; i <= n - 1; i++) {
      cout << 0;
    }
  } else {
    for (int i = 1; i <= n; i++) {
      cout << k;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  solve();
  return 0;
}
