#include <bits/stdc++.h>
using namespace std;
int i, j, a, b;
int main() {
  int n, f = 0;
  cin >> n;
  int ar[n];
  for (i = 0; i < n; i++) {
    cin >> ar[i];
    ar[i] -= n - i - 1;
  }
  sort(ar, ar + n);
  for (i = 1; i < n; i++) {
    if (ar[i] == ar[i - 1]) {
      f = 1;
      cout << ":("
           << "\n";
      break;
    }
  }
  if (f == 0) {
    for (i = 0; i < n; i++) {
      cout << ar[i] + n - i - 1 << " ";
    }
  }
  return 0;
}
