#include <bits/stdc++.h>
using namespace std;
pair<int, int> p[1100];
int N, M;
int a[1100];
int out[1100];
int main() {
  int i, j;
  scanf("%d%d", &N, &M);
  for (i = 0; i < M; ++i) {
    scanf("%d", &a[i]);
    p[i] = make_pair(-a[i], i + 1);
  }
  sort(p, p + M);
  int mx = p[0].first;
  int rest = 0;
  for (i = 1; i < M; ++i) rest -= p[i].first;
  int sum = 0;
  for (i = 0; i < M; ++i) {
    int t1 = -p[i].first;
    if (t1 > N / 2) t1 = N / 2;
    sum += t1;
  }
  if (sum < N) {
    printf("-1\n");
  } else if (rest < (N / 2 + N % 2)) {
    printf("-1\n");
  } else {
    vector<int> v;
    if (N % 2) {
      for (i = 1; i < N; i += 2) v.push_back(i);
      for (i = 0; i < N; i += 2) v.push_back(i);
    } else {
      for (i = 0; i < N; i += 2) v.push_back(i);
      for (i = 1; i < N; i += 2) v.push_back(i);
    }
    reverse(v.begin(), v.end());
    for (i = 0; i < M && (!v.empty()); ++i) {
      int t1 = -p[i].first;
      if (t1 > N / 2) t1 = N / 2;
      for (j = 0; j < t1 && (!v.empty()); ++j) {
        out[v.back()] = p[i].second;
        v.pop_back();
      }
    }
    for (i = 0; i < N; ++i) {
      if (i) printf(" ");
      printf("%d", out[i]);
    }
    printf("\n");
  }
  return 0;
}
