import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int a = scan.nextInt();
        int b = scan.nextInt();

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

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

        System.out.println((a*(a-1))/2 + (b*(b-1))/2);
    } main {
        Scanner scan = new Scanner(System.in);
        int a = scan.nextInt();
        int b = scan.nextInt();

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

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

        System.out.println((a*(a-1))/2 + (b*(b-1))/2);
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int a = scan.nextInt();
        int b = scan.nextInt();

        System.out.println((a*(a-1))/2 + (b*(b-1))/2);
    }
}