import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int result = 0;
        for (int i = even - 1; i > 0; i--){
            result = result + i;
        }
        for (int i = odd - 1; i > 0; i--){
            result = result + i;
        }
        System.out.println(result);

    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int result = 0;
        for (int i = even - 1; i > 0; i--){
            result = result + i;
        }
        for (int i = odd - 1; i > 0; i--){
            result = result + i;
        }
        System.out.println(result);

    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int result = 0;
        for (int i = even - 1; i > 0; i--){
            result = result + i;
        }
        for (int i = odd - 1; i > 0; i--){
            result = result + i;
        }
        System.out.println(result);

    } main {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int result = 0;
        for (int i = even - 1; i > 0; i--){
            result = result + i;
        }
        for (int i = odd - 1; i > 0; i--){
            result = result + i;
        }
        System.out.println(result);

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int even = sc.nextInt(); even sc.nextInt() sc.nextInt sc int odd = sc.nextInt(); odd sc.nextInt() sc.nextInt sc int result = 0; result 0 for (int i = even - 1; i > 0; i--){
            result = result + i;
        } int i = even - 1; int i = even - 1; i even - 1 even 1 i > 0 i 0 i-- i-- i {
            result = result + i;
        } {
            result = result + i;
        } result = result + i result result + i result i for (int i = odd - 1; i > 0; i--){
            result = result + i;
        } int i = odd - 1; int i = odd - 1; i odd - 1 odd 1 i > 0 i 0 i-- i-- i {
            result = result + i;
        } {
            result = result + i;
        } result = result + i result result + i result i System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int result = 0;
        for (int i = even - 1; i > 0; i--){
            result = result + i;
        }
        for (int i = odd - 1; i > 0; i--){
            result = result + i;
        }
        System.out.println(result);

    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int result = 0;
        for (int i = even - 1; i > 0; i--){
            result = result + i;
        }
        for (int i = odd - 1; i > 0; i--){
            result = result + i;
        }
        System.out.println(result);

    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int result = 0;
        for (int i = even - 1; i > 0; i--){
            result = result + i;
        }
        for (int i = odd - 1; i > 0; i--){
            result = result + i;
        }
        System.out.println(result);

    }
}
