#include <bits/stdc++.h>
using namespace std;
using LL = long long;
using pii = pair<int, int>;
const LL INF = 9223372036854775807LL;
int main() {
  int n;
  cin >> n;
  vector<int> aa(n);
  for (int i = 0; i < int(n); ++i) cin >> aa[i];
  for (int i = 0; i < int(n); ++i) aa[i] -= (n - 1 - i);
  sort((aa).begin(), (aa).end());
  for (int i = 0; i < int(n - 1); ++i) {
    if (aa[i] == aa[i + 1]) {
      cout << ":(" << endl;
      return 0;
    }
  }
  for (int i = 0; i < int(n); ++i) {
    if (i) cout << " ";
    cout << (aa[i] + n - 1 - i);
  }
  cout << endl;
  return 0;
}
