#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 5;
int a[maxn];
int main() {
  ios::sync_with_stdio(false);
  int n;
  bool flag = true;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    scanf("%d", &a[i]);
    a[i] += i;
  }
  sort(a, a + n);
  for (int i = 0; i < n; ++i) a[i] -= i;
  for (int i = 1; i < n; ++i) {
    if (a[i - 1] > a[i]) {
      flag = false;
      break;
    }
  }
  if (flag) {
    for (int i_ = 0; i_ < n; ++i_) printf("%d ", a[i_]);
    putchar('\n');
  } else {
    puts(":(");
  }
  return 0;
}
