#include <bits/stdc++.h>
using namespace std;
map<int,int> mp;
int n,k,arr[1000100];
int main()
{
int ans=0;
cin>>n>>k;
for(int i=0;i<n;i++)
{
cin>>arr[i];
mp[arr[i]]++;
}
for(int i=0;i<n;i++)
{
ans+=mp[arr[i]+k];
}
cout<<ans<<endl;
// your code goes here
return 0;
}
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