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