#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
int a[N];
int main() {
  ios ::sync_with_stdio(0);
  int n;
  cin >> n;
  for (int i = int(1); i <= int(n); i++) {
    cin >> a[i];
    a[i] += i;
  }
  sort(a + 1, a + n + 1);
  for (int i = int(1); i <= int(n); i++) a[i] -= i;
  for (int i = int(1); i <= int(n - 1); i++) {
    if (a[i] > a[i + 1]) {
      cout << ":(" << endl;
      return 0;
    }
  }
  for (int i = int(1); i <= int(n); i++) {
    cout << a[i] << ' ';
  }
  cout << endl;
  return 0;
}
