import java.util.*;
public class Main
 {
     public static void main(String[] args)
   {
     Scanner s=new Scanner(System.in);
     int n=s.nextInt();
     int m=s.nextInt();
     int ans=0;
    ans=(n*(n-1)/2)+(m*(m-1)/2);
    System.out.println(ans);
   } 
} import java.util.*; util.* java public class Main
 {
     public static void main(String[] args)
   {
     Scanner s=new Scanner(System.in);
     int n=s.nextInt();
     int m=s.nextInt();
     int ans=0;
    ans=(n*(n-1)/2)+(m*(m-1)/2);
    System.out.println(ans);
   } 
} Main public static void main(String[] args)
   {
     Scanner s=new Scanner(System.in);
     int n=s.nextInt();
     int m=s.nextInt();
     int ans=0;
    ans=(n*(n-1)/2)+(m*(m-1)/2);
    System.out.println(ans);
   } main {
     Scanner s=new Scanner(System.in);
     int n=s.nextInt();
     int m=s.nextInt();
     int ans=0;
    ans=(n*(n-1)/2)+(m*(m-1)/2);
    System.out.println(ans);
   } Scanner s=new Scanner(System.in); s new Scanner(System.in) int n=s.nextInt(); n s.nextInt() s.nextInt s int m=s.nextInt(); m s.nextInt() s.nextInt s int ans=0; ans 0 ans=(n*(n-1)/2)+(m*(m-1)/2) ans (n*(n-1)/2)+(m*(m-1)/2) (n*(n-1)/2) n*(n-1) n (n-1) n 1 2 (m*(m-1)/2) m*(m-1) m (m-1) m 1 2 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main
 {
     public static void main(String[] args)
   {
     Scanner s=new Scanner(System.in);
     int n=s.nextInt();
     int m=s.nextInt();
     int ans=0;
    ans=(n*(n-1)/2)+(m*(m-1)/2);
    System.out.println(ans);
   } 
} public class Main
 {
     public static void main(String[] args)
   {
     Scanner s=new Scanner(System.in);
     int n=s.nextInt();
     int m=s.nextInt();
     int ans=0;
    ans=(n*(n-1)/2)+(m*(m-1)/2);
    System.out.println(ans);
   } 
} Main
import java.util.*;
public class Main
 {
     public static void main(String[] args)
   {
     Scanner s=new Scanner(System.in);
     int n=s.nextInt();
     int m=s.nextInt();
     int ans=0;
    ans=(n*(n-1)/2)+(m*(m-1)/2);
    System.out.println(ans);
   } 
}