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

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