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 comboN = (N*(N-1))/2;
        int comboM = (M*(M-1))/2;

        System.out.println(comboN+comboM);
    }
} 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 comboN = (N*(N-1))/2;
        int comboM = (M*(M-1))/2;

        System.out.println(comboN+comboM);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int M = sc.nextInt();

        int comboN = (N*(N-1))/2;
        int comboM = (M*(M-1))/2;

        System.out.println(comboN+comboM);
    } main {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int M = sc.nextInt();

        int comboN = (N*(N-1))/2;
        int comboM = (M*(M-1))/2;

        System.out.println(comboN+comboM);
    } 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 comboN = (N*(N-1))/2; comboN (N*(N-1))/2 (N*(N-1)) N (N-1) N 1 2 int comboM = (M*(M-1))/2; comboM (M*(M-1))/2 (M*(M-1)) M (M-1) M 1 2 System.out.println(comboN+comboM) System.out.println System.out System System.out comboN+comboM comboN comboM 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 comboN = (N*(N-1))/2;
        int comboM = (M*(M-1))/2;

        System.out.println(comboN+comboM);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int M = sc.nextInt();

        int comboN = (N*(N-1))/2;
        int comboM = (M*(M-1))/2;

        System.out.println(comboN+comboM);
    }
} 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 comboN = (N*(N-1))/2;
        int comboM = (M*(M-1))/2;

        System.out.println(comboN+comboM);
    }
}
