#include <bits/stdc++.h>
using namespace std;
const int limit = 200005;
int in[limit];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &in[i]);
  for (int i = 1; i <= n; i++) in[i] += i;
  sort(in, in + n + 1);
  for (int i = 1; i <= n; i++) in[i] -= i;
  bool ok = true;
  for (int i = 1; i <= n - 1; i++) {
    if (in[i] > in[i + 1]) {
      ok = false;
      break;
    }
  }
  if (ok) {
    for (int i = 1; i <= n; i++) printf("%d ", in[i]);
    printf("\n");
  } else
    printf(":(");
  return 0;
}
