#include<iostream>
using namespace std;
long long n,c,a[30000005],b[30000005],sum;
int main(){
    cin>>n>>c;
    for(int i=1;i<=n;i++){
        cin>>a[i];
        b[a[i]]++;
    }
    for(int i=1;i<=n;i++){
        if(a[i]<c) continue;
        sum+=b[a[i]-c];
    }
    cout<<sum;
    return 0;
}