#include <bits/stdc++.h>
using namespace std;
#define int long long int
#define double long double
inline int power(int a, int b) {
int x = 1;
while (b) {
if (b & 1) x *= a;
a *= a;
b >>= 1;
}
return x;
}
const int M = 1000000007;
const int N = 3e5+9;
const int INF = 2e9+1;
const int LINF = 2000000000000000001;
//_ ***************************** START Below *******************************
vector<int> a;
void consistency(int n, int k) {
unordered_map<int,int> mp;
int ans = 0;
for(int i=0; i<n; i++){
if(mp.count(a[i] - k)){
ans += mp[a[i]-k];
}
mp[a[i]]++;
}
cout << ans << endl;
}
void solve() {
int n, k;
cin >> n >> k;
a.resize(n);
for(int i=0; i<n; i++) cin >> a[i];
consistency(n, k) ;
}
int32_t main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int t = 1;
while (t--) {
solve();
}
return 0;
}
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