#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
int n, v[200002];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n;
  for (int i = 1; i <= n; ++i) cin >> v[i], v[i] += i;
  sort(v + 1, v + n + 1);
  for (int i = 1; i <= n; ++i) v[i] -= i;
  for (int i = 2; i <= n; ++i)
    if (v[i - 1] > v[i]) {
      cout << ":(";
      return 0;
    }
  for (int i = 1; i <= n; ++i) cout << v[i] << " ";
  return 0;
}
