#include <cstdio>
#include <cstdlib>
int n, c, s, t, k, a[200010];
inline int cmp(const void *a, const void *b) {
    return *(int*)a - *(int*)b;
}
int main() {
    freopen("dec.in","r",stdin);
    freopen("dec.out","w",stdout);
    scanf("%d %d", &n, &c);
    for(int i=0; i<n; i++)
        scanf("%d", a+i);
    qsort(a, n, sizeof(a[0]), cmp);
    for(int i=0; i<n-1; i++) {
        for(s=i; s<n; s++) if(a[s] == a[i] + c) break;
        for(t=s; t<n; t++) if(a[t] > a[i] + c) break;
        k += t - s;
    }
    printf("%d\n", k);
    return 0;
}