#![allow(unused_imports)]

fn main() {
    input! {
        n: usize, d: i32,
        a: [i32; n],
    }
    let mut l = HashMap::<i32, usize>::new();
    let mut r = HashMap::<i32, usize>::new();
    for &a in &a {
        *r.entry(a).or_default() += 1;
    }
    let mut ans = 0usize;
    for a in a {
        *r.entry(a).or_default() -= 1;
        ans += l.get(&(a-d)).unwrap_or(&0) 
        * r.get(&(a+d)).unwrap_or(&0) ;
        *l.entry(a).or_default() += 1;
    }
    println!("{ans}");
}

use proconio::{input, marker::*};
use itertools::{iproduct, izip, Itertools as _};
use std::{cmp::Reverse, collections::*};

#[macro_export]
macro_rules! chmax {
    ($a:expr, $b:expr) => {{
        let tmp = $b;
        if $a < tmp {
            $a = tmp;
            true
        } else {
            false
        }
    }};
}

#[macro_export]
macro_rules! chmin {
    ($a:expr, $b:expr) => {{
        let tmp = $b;
        if $a > tmp {
            $a = tmp;
            true
        } else {
            false
        }
    }};
}

#[macro_export]
/// mvec![]
macro_rules! mvec {
    ($val:expr; ()) => {
        $val
    };
    ($val:expr; ($size:expr $(,$rest:expr)*)) => {
        vec![mvec![$val; ($($rest),*)]; $size]
    };
}