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();

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

		System.out.println(n * (n - 1) / 2 + m * (m - 1) / 2);
	}
} Main public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int m = sc.nextInt();

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

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int m = sc.nextInt();

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

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

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int m = sc.nextInt();

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

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