#include<bits/stdc++.h>
#define int long long
using namespace std;
template<typename T>T read(){
	T res=0ll,f=1ll;
	char ch=getchar();
	for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-1ll;
	for(;isdigit(ch);ch=getchar()) res=(res<<3ll)+(res<<1ll)+(ch^48ll);
	return res*f;
}
template<typename T>void write(T x){
	if(x<0ll) x=-x,putchar('-');
	int sta[20ll],top=0ll;
	do{
			sta[++top]=x%10ll+'0';
		x/=10ll;
	}while(x);
	while(top){
		putchar(sta[top--]);
	}
}
const int N=1e6+5;
int n,c,a[N],ans,cnt[N<<1],sum[N<<1];
int C(int x,int y){
	int res=1ll;
	for(int i(1);i<=y;++i) res=res*(x-y+i)/(i);
	return res;
}
signed main(){
	freopen("Triplets.in","r",stdin);
	freopen("Triplets.out","w",stdout);
	n=read<int>(),c=read<int>();
	for(int i(1ll);i<=n;++i){
		a[i]=read<int>();
		++cnt[a[i]];
		++cnt[a[i]+c];
	}
	for(int i(1ll);i<=(c<<1ll);++i){
		sum[i]=sum[i-1ll]+cnt[i];
	}
	for(int i(1ll);i<=n;++i){
		ans+=C(sum[a[i]+(c>>1ll)]-sum[a[i]],2ll);
	}
	for(int i(1ll);i<=c;++i){
		if(cnt[i]>=3ll){
			ans+=C(cnt[i],3ll);
		}
		if(cnt[i]>=2ll){
			ans+=C(cnt[i],2ll)*(sum[i+(c%2ll)+(c>>1ll)-1ll]-sum[i]);
		}
	}
	ans=C(n,3ll)-ans;
	write(ans);
	return 0;
}