#include <bits/stdc++.h>
using namespace std;
int main() {
int size,k;
cin>>size>>k;
int A[size];
for(int i = 0 ; i<size ; i++){
cin>>A[i];
}
map<int,int>hashmap;
int totalCount = 0;
for(int i = size-1 ; i>=0 ; i--){
if(hashmap.find(A[i]-k)!=hashmap.end()){
totalCount += hashmap[(A[i]-k)];
}
if(hashmap.find(A[i]+k)!=hashmap.end()){
totalCount += hashmap[(A[i]+k)];
}
hashmap[A[i]]++;
}
cout<<totalCount<<endl;
return 0;
}
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