#include <bits/stdc++.h>
using namespace std;
const int N = (int)2e5 + 5;
const int inf = (int)1e9 + 7;
int n;
int a[N], ans[N];
vector<pair<int, int> > b;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%d", a + i);
    b.push_back(make_pair(a[i] + i, i));
  }
  sort(b.begin(), b.end());
  for (int i = 0; i < (int)((b).size()); ++i) {
    ans[i + 1] = a[b[i].second] - (i + 1 - b[i].second);
  }
  for (int i = 1; i <= n; ++i) {
    if (ans[i] < 0 || (i < n && ans[i] > ans[i + 1])) {
      printf(":(");
      return 0;
    }
  }
  for (int i = 1; i <= n; ++i) {
    printf("%d ", ans[i]);
  }
  return 0;
}
