description: Monocarp is the coach of the Berland State University programming teams. He decided to compose a problemset for a training session for his teams.
  
  Monocarp has n problems that none of his students have seen yet. The i-th problem has a topic a_i (an integer from 1 to n) and a difficulty b_i (an integer from 1 to n). All problems are different, that is, there are no two tasks that have the same topic and difficulty at the same time.
  
  Monocarp decided to select exactly 3 problems from n problems for the problemset. The problems should satisfy at least one of two conditions (possibly, both):
  
    * the topics of all three selected problems are different; 
    * the difficulties of all three selected problems are different. 
  
  
  
  Your task is to determine the number of ways to select three problems for the problemset.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 50000) — the number of testcases.
  
  The first line of each testcase contains an integer n (3 ≤ n ≤ 2 ⋅ 10^5) — the number of problems that Monocarp have.
  
  In the i-th of the following n lines, there are two integers a_i and b_i (1 ≤ a_i, b_i ≤ n) — the topic and the difficulty of the i-th problem.
  
  It is guaranteed that there are no two problems that have the same topic and difficulty at the same time.
  
  The sum of n over all testcases doesn't exceed 2 ⋅ 10^5.
  
  Output
  
  Print the number of ways to select three training problems that meet either of the requirements described in the statement.
  
  Example
  
  Input
  
  
  2
  4
  2 4
  3 4
  2 1
  1 3
  5
  1 5
  2 4
  3 3
  4 2
  5 1
  
  
  Output
  
  
  3
  10
  
  Note
  
  In the first example, you can take the following sets of three problems:
  
    * problems 1, 2, 4; 
    * problems 1, 3, 4; 
    * problems 2, 3, 4. 
  
  
  
  Thus, the number of ways is equal to three.
solution:  import java.util.*;
   import java.lang.*;
   import java.io.*;
  
  public class D_Training_Session
   {
       static int M = 1_000_000_007;
       static final PrintWriter out =new PrintWriter(System.out);
       static final FastReader fs = new FastReader();
       static boolean prime[];
       public static void main (String[] args) throws java.lang.Exception
       {
             
             int t= fs.nextInt();
             for(int i=0;i<t;i++)
             {
                 int n= fs.nextInt();
                 int a[]=new int[n];
                 int b[]=new int[n];
                 HashMap<Integer, ArrayList<Integer>> hm1=new HashMap<Integer,ArrayList<Integer>>();
                 HashMap<Integer, ArrayList<Integer>> hm3=new HashMap<Integer,ArrayList<Integer>>();
                //HashMap<Integer, Integer> hm2=new HashMap<Integer,Integer>();
                 for(int j=0;j<n;j++){
                      a[j]=fs.nextInt();
                      b[j]=fs.nextInt();
                      if(hm1.get(a[j])==null){
                      hm1.put(a[j],new ArrayList<Integer>());
                  }
                      if(hm3.get(b[j])==null){
                      hm3.put(b[j],new ArrayList<Integer>());
                  }
                      hm1.get(a[j]).add(b[j]);
                      hm3.get(b[j]).add(a[j]);
                     
                 }
                 long ans=((long)n*(long)(n-1)*(long)(n-2))/6;
                 for(Map.Entry<Integer,ArrayList<Integer>> entry:hm1.entrySet()){
                    // int ai=entry.getKey();
                     for(int jj=0;jj<entry.getValue().size();jj++){
                      ans=ans-(long)(entry.getValue().size()-1)*(long)(hm3.get(entry.getValue().get(jj)).size()-1);
                     }                 
                 }
                 out.println(ans);
             }
             out.flush();
    }
    public static long power(long x, long y)
    {
        long temp;
        if (y == 0)
            return 1;
        temp = power(x, y / 2);
  
        if (y % 2 == 0)
            return modMult(temp,temp);
        else {
            if (y > 0)
                return modMult(x,modMult(temp,temp));
            else
                return (modMult(temp,temp)) / x;
        }
    }
    static void sieveOfEratosthenes(int n)
      {
           prime = new boolean[n + 1];
          for (int i = 0; i <= n; i++)
              prime[i] = true;
              prime[0]=false;
              if(1<=n)
              prime[1]=false;
          for (int p = 2; p * p <= n; p++)
          {
              
              if (prime[p] == true)
              {
                 
                  for (int i = p * p; i <= n; i += p)
                      prime[i] = false;
              }
          }
      }
           static class FastReader 
           {
           BufferedReader br;
           StringTokenizer st;
    
           public FastReader()
           {
               br = new BufferedReader(
                   new InputStreamReader(System.in));
           }
    
           String next()
           {
               while (st == null || !st.hasMoreElements()) {
                   try {
                       st = new StringTokenizer(br.readLine());
                       }
                   catch (IOException e) {
                       e.printStackTrace();
                       }
           }
               return st.nextToken();
           }
    
           int nextInt() { return Integer.parseInt(next()); }
    
           long nextLong() { return Long.parseLong(next()); }
    
           double nextDouble()
           {
               return Double.parseDouble(next());
           }
    
           String nextLine()
           {
               String str = "";
               try {
                   str = br.readLine();
               }
               catch (IOException e) {
                   e.printStackTrace();
               }
               return str;
           }
   int [] arrayIn(int n) throws IOException
       {
           int  arr[] = new int[n];
           for(int i=0; i<n; i++)
           {
               arr[i] = nextInt();
           }
           return arr;
       }
       }
       
       public static class Pairs implements Comparable<Pairs>
       {
           int value,index;
           Pairs(int value, int index)
           {
               this.value = value;
               this.index = index;
           }
           public int compareTo(Pairs p)
           {
               return Integer.compare(this.value, p.value);
           }
       }
       static final Random random = new Random();
    
       static void ruffleSort(int arr[])
       {
           int n = arr.length;
           for(int i=0; i<n; i++)
           {
               int j = random.nextInt(n),temp = arr[j];
               arr[j] = arr[i];
               arr[i] = temp;
           }
           Arrays.sort(arr);
       }
       static long nCk(int n, int k) {
           return (modMult(fact(n),fastexp(modMult(fact(n-k),fact(k)),M-2)));
       }
    
       static long fact (long n) {
    
           long fact =1;
           for(int i=1; i<=n; i++) {
               fact = modMult(fact,i);
           }
           return fact%M;
       }
    
       static long modMult(long a,long b) {
           return a*b%M;
       }
    
       static long fastexp(long x, int y){
           if(y==1) return x;
    
           long ans = fastexp(x,y/2);
           if(y%2 == 0) return modMult(ans,ans);
           else return modMult(ans,modMult(ans,x));
       }
   }