#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll n,c,a[2000005],b[100000000],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;
}
```cpp