static void Main(string[] args)
{
string[] input = Console.ReadLine().Split(' ');
string[] soldiers = Console.ReadLine().Split(' ');
int[] sol = new int[soldiers.Length];
int diff = int.Parse(input[1]);
for (int i = 0; i < soldiers.Length; i++)
sol[i] = int.Parse(soldiers[i]);
int result = 0;
for (int i = 0; i < sol.Length; i++)
{
for (int a = 0; a < sol.Length; a++)
{
if (a == i)
continue;
if (Math.Abs(sol[i] - sol[a]) <= diff)
result++;
}
}
Console.WriteLine(result);
Console.ReadLine();
}