import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
    @SuppressWarnings("deprecation")
	public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	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.io.FileNotFoundException; FileNotFoundException java.io import java.util.Scanner; Scanner java.util public class Main {
    @SuppressWarnings("deprecation")
	public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	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 @SuppressWarnings("deprecation")
	public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	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 {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	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 {
    @SuppressWarnings("deprecation")
	public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	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 {
    @SuppressWarnings("deprecation")
	public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	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.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
    @SuppressWarnings("deprecation")
	public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	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);
    }
}