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

int cmp_int (const void *ap, const void *bp) {
  int a = *(int *)ap;
  int b = *(int *)bp;
  
  if (a < b) {
    return -1;
  }
  
  if (a > b) {
    return 1;
  }
  
  return 0;
}

int main () {
  int n = 0;
  int m = 0;
  int a[300000] = {};
  
  int res = 0;
  
  long long ans = 0LL;
  int idx = 0;
  
  res = scanf("%d", &n);
  res = scanf("%d", &m);
  for (int i = 0; i < n; i++) {
    res = scanf("%d", a+i);
  }
  
  if (m%2 == 1) {
    printf("0\n");
    return 0;
  }
  
  qsort(a, n, sizeof(int), cmp_int);
  for (int i = 0; i < n; i++) {
    while (idx < n && a[idx] < a[i]+m/2) {
      idx++;
    }
    if (idx < n && a[idx] == a[i]+m/2) {
      ans += 1LL;
    }
  }
  
  ans *= (long long)(n-2);
  printf("%lld\n", ans);
  return 0;
}