import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int m = scanner.nextInt();

		int nSum = n * (n - 1) / 2;
		int mSum = m * (m - 1) / 2;

		int sum = nSum + mSum;

		System.out.println(sum);

		scanner.close();

	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int m = scanner.nextInt();

		int nSum = n * (n - 1) / 2;
		int mSum = m * (m - 1) / 2;

		int sum = nSum + mSum;

		System.out.println(sum);

		scanner.close();

	}

} Main public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int m = scanner.nextInt();

		int nSum = n * (n - 1) / 2;
		int mSum = m * (m - 1) / 2;

		int sum = nSum + mSum;

		System.out.println(sum);

		scanner.close();

	} main {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int m = scanner.nextInt();

		int nSum = n * (n - 1) / 2;
		int mSum = m * (m - 1) / 2;

		int sum = nSum + mSum;

		System.out.println(sum);

		scanner.close();

	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int n = scanner.nextInt(); n scanner.nextInt() scanner.nextInt scanner int m = scanner.nextInt(); m scanner.nextInt() scanner.nextInt scanner int nSum = n * (n - 1) / 2; nSum n * (n - 1) / 2 n * (n - 1) n (n - 1) n 1 2 int mSum = m * (m - 1) / 2; mSum m * (m - 1) / 2 m * (m - 1) m (m - 1) m 1 2 int sum = nSum + mSum; sum nSum + mSum nSum mSum System.out.println(sum) System.out.println System.out System System.out sum scanner.close() scanner.close scanner String[] args args public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int m = scanner.nextInt();

		int nSum = n * (n - 1) / 2;
		int mSum = m * (m - 1) / 2;

		int sum = nSum + mSum;

		System.out.println(sum);

		scanner.close();

	}

} public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int m = scanner.nextInt();

		int nSum = n * (n - 1) / 2;
		int mSum = m * (m - 1) / 2;

		int sum = nSum + mSum;

		System.out.println(sum);

		scanner.close();

	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int m = scanner.nextInt();

		int nSum = n * (n - 1) / 2;
		int mSum = m * (m - 1) / 2;

		int sum = nSum + mSum;

		System.out.println(sum);

		scanner.close();

	}

}
