#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv){
    unsigned n, k, i, j, br=0, *num;
    scanf("%d %d", &n, &k);
    num=calloc(n, sizeof(unsigned));
    for (i=0; i<n; i++)
        scanf("%d", &num[i]);
    for (i=0; i<n; i++)
    for (j=1; j<n; j++)
    if (num[j]-num[i]==k) br++;
    printf("%d", br);
    free(num);
    return 0;
}