#include <bits/stdc++.h>
using namespace std;
void RI() {}
template <typename... T>
void RI(int& head, T&... tail) {
  scanf("%d", &head);
  RI(tail...);
}
mt19937 rng(0x5EED);
int randint(int lb, int ub) {
  return uniform_int_distribution<int>(lb, ub)(rng);
}
int N, T;
int main(int argc, char** argv) {
  cin >> N >> T;
  if (T == 10) {
    if (N == 1) {
      puts("-1");
    } else {
      for (int i = 1; i < N; i++) putchar('1');
      puts("0");
    }
  } else {
    for (int i = 0; i < N; i++) putchar('0' + T);
    puts("");
  }
  return 0;
}
