#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;

long long int make_and_count(long long int array[], int n, long long int d) {
    long long int count = 0;
    long long int table[n][n]={},table2[n][n]={};

    for(long long int i=0;i<n;i++) {
        for(long long int j=i+1;j<n;j++) {
            if(array[j] - array[i] == d) {
                table[i][j] = table[i][j-1] + 1;
            } else {
                table[i][j] = table[i][j-1];
            }
        }
    }
    for(long long int j=n-1;j>=0;j--) {
        for(long long int i=j-1;i>=0;i--) {
            if(array[j] - array[i] == d) {
                table2[i][j] = table2[i+1][j] + 1;
            } else {
                table2[i][j] = table2[i+1][j];
            }
        }
    }
    for(long long int i=0;i<n;i++) {
        count += table2[0][i] * table[i][n-1];
    }
    return count;
}


int main(){
    long long int n;
    long long int d;
    
    cin >> n >> d;

    long long int array[n];
    
    for(long long int i=0;i<n;i++) cin >> array[i];

    long long int count = make_and_count(array, n, d);

    cout << count << endl;

    return 0;
}