#include <bits/stdc++.h>
using namespace std;
int n;
int a[216000];
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    a[i] += i;
  }
  sort(a, a + n);
  for (int i = 0; i < n; i++) {
    a[i] -= i;
  }
  for (int i = 0; i < n - 1; i++) {
    if (a[i] > a[i + 1]) {
      cout << ":(" << endl;
      return 0;
    }
  }
  for (int i = 0; i < n; i++) {
    if (i) cout << " ";
    cout << a[i];
  }
  cout << endl;
  return 0;
}
