#include <bits/stdc++.h>
using namespace std;
const long double pi = 3.1415926535897932384626433;
const long long inf = 1e18;
const long long mod = 1e9 + 7;
void solve() {
  long long n;
  cin >> n;
  vector<long long> a(n);
  vector<vector<long long> > cnt(100001);
  long long me = 0;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    cnt[a[i]].push_back(i);
    me = max(me, a[i]);
  }
  bool ok = 1;
  for (long long i = me; i >= 2; i--) {
    if (cnt[i].size() > cnt[i - 1].size()) {
      ok = 0;
      break;
    }
  }
  if (!ok) {
    cout << "-1\n";
    return;
  }
  vector<long long> ans(n);
  long long c = 0;
  for (long long i = 1; i <= me; i++) {
    long long k = 1;
    for (auto x : cnt[i]) {
      ans[x] = k;
      k++;
      c = max(c, k);
    }
  }
  cout << c - 1 << "\n";
  for (long long i = 0; i < n; i++) {
    cout << ans[i] << " ";
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long t;
  t = 1;
  while (t--) {
    solve();
  }
}
