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