#include <bits/stdc++.h>
using namespace std;
const int N = 200008;
int n, a[N];
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]), a[i] += i;
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; i++) a[i] -= i;
  for (int i = 1; i <= n - 1; i++)
    if (a[i] > a[i + 1]) {
      printf(":(\n");
      return 0;
    }
  for (int i = 1; i <= n; i++) printf("%d ", a[i]);
  printf("\n");
  return 0;
}
