#include<iostream>
#include<cmath>
#include<cstdio>
#include<algorithm>
using namespace std;
int a[2002];
int main()
{
	int n,c,ans=0;
	cin>>n>>c;
	for(int i=1;i<=n;i++)cin>>a[i];
	for(int i=1;i<=n;i++)
		for(int j=2;j<=n;j++)
			if(abs(a[i]-a[j])==c)ans++;
	cout<<ans;
}

哪错了?