import java.util.*;
public class Main{
	public static void main(String[] args){
    	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[] args){
    	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[] args){
    	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[] args args public class Main{
	public static void main(String[] args){
    	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[] args){
    	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[] args){
    	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));
    }
}