import java.lang.reflect.Array;
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();

        int ans = n * (n - 1) / 2 + m * (m - 1) / 2;

        System.out.println(ans);
    }

} import java.lang.reflect.Array; Array java.lang.reflect 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();

        int ans = n * (n - 1) / 2 + m * (m - 1) / 2;

        System.out.println(ans);
    }

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

        int ans = n * (n - 1) / 2 + m * (m - 1) / 2;

        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();

        int ans = n * (n - 1) / 2 + m * (m - 1) / 2;

        System.out.println(ans);
    } 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 int ans = n * (n - 1) / 2 + m * (m - 1) / 2; ans 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 System.out.println(ans) System.out.println System.out System System.out ans 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();

        int ans = n * (n - 1) / 2 + m * (m - 1) / 2;

        System.out.println(ans);
    }

} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();

        int ans = n * (n - 1) / 2 + m * (m - 1) / 2;

        System.out.println(ans);
    }

} Main
import java.lang.reflect.Array;
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();

        int ans = n * (n - 1) / 2 + m * (m - 1) / 2;

        System.out.println(ans);
    }

}
