import std;

void main () {
    int N, D;
    readln.read(N, D);
    auto A = readln.split.to!(int[]);

    int[int] pre, suf;
    foreach (i; 0 .. N) {
        suf[A[i]]++;
    }

    long ans = 0;
    foreach (i; 0 .. N) {
        suf[A[i]]--;

        ans += 1L * pre.get(A[i] - D, 0) * suf.get(A[i] + D, 0);

        pre[A[i]]++;
    }

    writeln(ans);
}

void read (T...) (string S, ref T args) {
    import std.conv : to;
    import std.array : split;
    auto buf = S.split;
    foreach (i, ref arg; args) {
        arg = buf[i].to!(typeof(arg));
    }
}