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();

        long x = n * (n - 1) / 2;
        long y = m * (m - 1) / 2;

        System.out.println(x + y);

    }

} 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();

        long x = n * (n - 1) / 2;
        long y = m * (m - 1) / 2;

        System.out.println(x + y);

    }

} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int m = sc.nextInt();

        long x = n * (n - 1) / 2;
        long y = m * (m - 1) / 2;

        System.out.println(x + y);

    } main {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int m = sc.nextInt();

        long x = n * (n - 1) / 2;
        long y = m * (m - 1) / 2;

        System.out.println(x + y);

    } 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 long x = n * (n - 1) / 2; x n * (n - 1) / 2 n * (n - 1) n (n - 1) n 1 2 long y = m * (m - 1) / 2; y m * (m - 1) / 2 m * (m - 1) m (m - 1) m 1 2 System.out.println(x + y) System.out.println System.out System System.out x + y x y 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();

        long x = n * (n - 1) / 2;
        long y = m * (m - 1) / 2;

        System.out.println(x + y);

    }

} public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int m = sc.nextInt();

        long x = n * (n - 1) / 2;
        long y = m * (m - 1) / 2;

        System.out.println(x + y);

    }

} 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();

        long x = n * (n - 1) / 2;
        long y = m * (m - 1) / 2;

        System.out.println(x + y);

    }

}
