#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<int> arr(n);
  for (int i = 0; i < n; ++i) cin >> arr[i];
  reverse(arr.begin(), arr.end());
  for (int i = 0; i < n; ++i) arr[i] -= i;
  sort(arr.rbegin(), arr.rend());
  for (int i = 0; i < n; ++i) arr[i] += i;
  reverse(arr.begin(), arr.end());
  for (int i = 0; i < n - 1; ++i)
    if (arr[i] > arr[i + 1]) {
      cout << ":(\n";
      return 0;
    }
  for (int i = 0; i < n; ++i) cout << arr[i] << " \n"[i == n - 1];
}
