import java.util.Scanner;

public class Main {
    public static void main(String[] argv) {
        Scanner scanner = new Scanner(System.in);

        String line = scanner.nextLine();

        String[] mn = line.split(" ");
        int m = Integer.parseInt(mn[0]);
        int n = Integer.parseInt(mn[1]);

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

        System.out.println(ans);

    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] argv) {
        Scanner scanner = new Scanner(System.in);

        String line = scanner.nextLine();

        String[] mn = line.split(" ");
        int m = Integer.parseInt(mn[0]);
        int n = Integer.parseInt(mn[1]);

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

        System.out.println(ans);

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

        String line = scanner.nextLine();

        String[] mn = line.split(" ");
        int m = Integer.parseInt(mn[0]);
        int n = Integer.parseInt(mn[1]);

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

        System.out.println(ans);

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

        String line = scanner.nextLine();

        String[] mn = line.split(" ");
        int m = Integer.parseInt(mn[0]);
        int n = Integer.parseInt(mn[1]);

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

        System.out.println(ans);

    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String line = scanner.nextLine(); line scanner.nextLine() scanner.nextLine scanner String[] mn = line.split(" "); mn line.split(" ") line.split line " " int m = Integer.parseInt(mn[0]); m Integer.parseInt(mn[0]) Integer.parseInt Integer mn[0] mn 0 int n = Integer.parseInt(mn[1]); n Integer.parseInt(mn[1]) Integer.parseInt Integer mn[1] mn 1 int ans = m  * (m - 1) / 2  + n * (n - 1) / 2; ans m  * (m - 1) / 2  + n * (n - 1) / 2 m  * (m - 1) / 2 m  * (m - 1) m (m - 1) m 1 2 n * (n - 1) / 2 n * (n - 1) n (n - 1) n 1 2 System.out.println(ans) System.out.println System.out System System.out ans String[] argv argv public class Main {
    public static void main(String[] argv) {
        Scanner scanner = new Scanner(System.in);

        String line = scanner.nextLine();

        String[] mn = line.split(" ");
        int m = Integer.parseInt(mn[0]);
        int n = Integer.parseInt(mn[1]);

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

        System.out.println(ans);

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

        String line = scanner.nextLine();

        String[] mn = line.split(" ");
        int m = Integer.parseInt(mn[0]);
        int n = Integer.parseInt(mn[1]);

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

        System.out.println(ans);

    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] argv) {
        Scanner scanner = new Scanner(System.in);

        String line = scanner.nextLine();

        String[] mn = line.split(" ");
        int m = Integer.parseInt(mn[0]);
        int n = Integer.parseInt(mn[1]);

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

        System.out.println(ans);

    }
}
