int main()
{
	int n;
	scanf("%d", &n);
	int* T = new int[n + 1];
	int* S = new int[n + 1];
	for (int i = 1; i <= n; i++)
	{
		scanf("%d", &T[i]);
		T[i] = T[i] * 10000 + i;
	}
	sort(T + 1, T + n + 1, less<int>());
	for (int i = 1; i <= n; i++) printf("%d ", T[i]%10000);
	printf("\n");
	int j = n;
	double ans = 0;
	for (int i = 1; i <= n; i++) ans = ans + T[i] / 10000 * (--j);
	ans = ans / n;
	printf("%.2lf", ans);
	return 0;
}