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.io.*;
  
  public class TrainingSession {
      public static void main(String[] args) {
          FastScanner scanner = new FastScanner();
          PrintWriter out = new PrintWriter(System.out);
          int T = scanner.nextInt();
          while(T-->0) {
              int n = scanner.nextInt();
              HashMap<Long, Long> a = new HashMap<>();
              HashMap<Long, Long> b = new HashMap<>();
              ArrayList<Integer>[] lists = new ArrayList[n+1];
              for(int i = 0; i <= n; i++) lists[i]=new ArrayList<>();
              for(int i = 0; i < n; i++) {
                  long ai = scanner.nextLong();
                  long bi = scanner.nextLong();
                  lists[(int)ai].add((int)bi);
                  Long aa = a.get(ai);
                  if (aa == null) a.put(ai, 1L);
                  else a.put(ai, aa + 1);
                  Long bb = b.get(bi);
                  if (bb == null) b.put(bi, 1L);
                  else b.put(bi, bb + 1);
              }
              long ans = (long)n * (n-1) * (n-2);
              ans /= 6;
              for(long key: a.keySet()) {
                  long val = a.get(key)-1;
                  for(long diff: lists[(int)key]) {
                      long other = b.get(diff)-1;
                      ans -= other * val;
                  }
              }
              out.println(ans);
          }
          out.flush();
      }
      public static class FastScanner {
          BufferedReader br;
          StringTokenizer st;
  
          public FastScanner(Reader in) {
              br = new BufferedReader(in);
          }
  
          public FastScanner() {
              this(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 readNextLine() {
              String str = "";
              try {
                  str = br.readLine();
              } catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
      }
  }
  