#include <bits/stdc++.h>
using namespace std;
long s[300000];
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> s[i];
    s[i] += i;
  }
  sort(s, s + n);
  for (int i = 0; i + 1 < n; i++) {
    if (s[i] == s[i + 1]) {
      cout << ":(" << endl;
      return 0;
    }
  }
  for (int h = 0; h < n; h++) {
    s[h] = s[h] - h;
    if (h == n - 1) {
      cout << s[h] << endl;
      continue;
    }
    cout << s[h] << " ";
  }
  return 0;
}
