#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  int arr[t];
  for (int i = 0; i < t; i++) {
    int y;
    cin >> y;
    y = y + i;
    arr[i] = y;
  }
  sort(arr, arr + t);
  for (int i = 0; i < t; i++) {
    arr[i] -= i;
  }
  int check = 1;
  for (int i = 0; i < t - 1; i++) {
    if (arr[i] > arr[i + 1]) {
      check = 0;
      break;
    }
  }
  if (check == 0)
    cout << ":( \n";
  else {
    for (int i = 0; i < t; i++) {
      cout << arr[i] << " ";
    }
  }
  return 0;
}
