#include <bits/stdc++.h>
using namespace std;
const int N = 200000 + 5;
set<pair<int, int> > st;
int a[N], id[N];
int n;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  for (int i = 1; i <= n; i++) {
    a[i] += i;
  }
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; i++) a[i] -= i;
  for (int i = 2; i <= n; i++) {
    if (a[i - 1] > a[i]) return puts(":("), 0;
  }
  for (int i = 1; i <= n; i++) printf("%d ", a[i]);
  puts("");
  return 0;
}
