import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        // int[] s = new int[n];

        // for (int i = 0; i < n; i++) {
        // s[i] = Integer.parseInt(sc.next());

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

        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 = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        // int[] s = new int[n];

        // for (int i = 0; i < n; i++) {
        // s[i] = Integer.parseInt(sc.next());

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

        sc.close();
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        // int[] s = new int[n];

        // for (int i = 0; i < n; i++) {
        // s[i] = Integer.parseInt(sc.next());

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

        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        // int[] s = new int[n];

        // for (int i = 0; i < n; i++) {
        // s[i] = Integer.parseInt(sc.next());

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

        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = Integer.parseInt(sc.next()); n Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int m = Integer.parseInt(sc.next()); m Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next 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 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 = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        // int[] s = new int[n];

        // for (int i = 0; i < n; i++) {
        // s[i] = Integer.parseInt(sc.next());

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

        sc.close();
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        // int[] s = new int[n];

        // for (int i = 0; i < n; i++) {
        // s[i] = Integer.parseInt(sc.next());

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

        sc.close();
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        // int[] s = new int[n];

        // for (int i = 0; i < n; i++) {
        // s[i] = Integer.parseInt(sc.next());

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

        sc.close();
    }
}