import java.util.*;
import java.io.*;

public class Main{
  public static void main(String[] args)throws Exception{
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int M = sc.nextInt();
    int a = (N*(N-1))/2;
    int b = (M*(M-1))/2;
    System.out.println(a+b);
  }
} import java.util.*; util.* java import java.io.*; io.* java public class Main{
  public static void main(String[] args)throws Exception{
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int M = sc.nextInt();
    int a = (N*(N-1))/2;
    int b = (M*(M-1))/2;
    System.out.println(a+b);
  }
} Main public static void main(String[] args)throws Exception{
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int M = sc.nextInt();
    int a = (N*(N-1))/2;
    int b = (M*(M-1))/2;
    System.out.println(a+b);
  } main {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int M = sc.nextInt();
    int a = (N*(N-1))/2;
    int b = (M*(M-1))/2;
    System.out.println(a+b);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int M = sc.nextInt(); M sc.nextInt() sc.nextInt sc int a = (N*(N-1))/2; a (N*(N-1))/2 (N*(N-1)) N (N-1) N 1 2 int b = (M*(M-1))/2; b (M*(M-1))/2 (M*(M-1)) M (M-1) M 1 2 System.out.println(a+b) System.out.println System.out System System.out a+b a b String[] args args public class Main{
  public static void main(String[] args)throws Exception{
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int M = sc.nextInt();
    int a = (N*(N-1))/2;
    int b = (M*(M-1))/2;
    System.out.println(a+b);
  }
} public class Main{
  public static void main(String[] args)throws Exception{
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int M = sc.nextInt();
    int a = (N*(N-1))/2;
    int b = (M*(M-1))/2;
    System.out.println(a+b);
  }
} Main
import java.util.*;
import java.io.*;

public class Main{
  public static void main(String[] args)throws Exception{
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int M = sc.nextInt();
    int a = (N*(N-1))/2;
    int b = (M*(M-1))/2;
    System.out.println(a+b);
  }
}