```cpp
map<long long,long long> m;
int main(){
cin>>n>>c;
for(int i=1;i<=n;i++){
cin>>a[i];
m[a[i]]++;
a[i]-=c;
}
for(int i=1;i<=n;i++)ans+=m[a[i]];
cout<<ans;
return 0;
}
```
by WJR2023 @ 2023-12-02 15:12:16