#include <bits/stdc++.h>
int main() {
  int n, t, z, q, m, c, k;
  int a[1000];
  scanf("%d %d", &n, &t);
  if (n == 1 && t == 10) {
    printf("-1");
  } else if (t == 10) {
    z = n - 1;
    for (c = 0; c < z; c++) {
      a[c] = 1;
    }
    a[z] = 0;
    for (c = 0; c < n; c++) {
      printf("%d", a[c]);
    }
  } else {
    for (c = 0; c < n; c++) {
      a[c] = t;
    }
    for (c = 0; c < n; c++) {
      printf("%d", a[c]);
    }
  }
  return 0;
}
