import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
			int n = s.nextInt();
			int m = s.nextInt();
			int x = n*(n-1)/2 + m*(m-1)/2;
			System.out.println(x);
		s.close();
	}

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

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
			int n = s.nextInt();
			int m = s.nextInt();
			int x = n*(n-1)/2 + m*(m-1)/2;
			System.out.println(x);
		s.close();
	}

} Main public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
			int n = s.nextInt();
			int m = s.nextInt();
			int x = n*(n-1)/2 + m*(m-1)/2;
			System.out.println(x);
		s.close();
	} main {
		Scanner s = new Scanner(System.in);
			int n = s.nextInt();
			int m = s.nextInt();
			int x = n*(n-1)/2 + m*(m-1)/2;
			System.out.println(x);
		s.close();
	} Scanner s = new Scanner(System.in); s new Scanner(System.in) int n = s.nextInt(); n s.nextInt() s.nextInt s int m = s.nextInt(); m s.nextInt() s.nextInt s int x = n*(n-1)/2 + m*(m-1)/2; x 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 System.out.println(x) System.out.println System.out System System.out x s.close() s.close s String[] args args public class Main {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
			int n = s.nextInt();
			int m = s.nextInt();
			int x = n*(n-1)/2 + m*(m-1)/2;
			System.out.println(x);
		s.close();
	}

} public class Main {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
			int n = s.nextInt();
			int m = s.nextInt();
			int x = n*(n-1)/2 + m*(m-1)/2;
			System.out.println(x);
		s.close();
	}

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

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
			int n = s.nextInt();
			int m = s.nextInt();
			int x = n*(n-1)/2 + m*(m-1)/2;
			System.out.println(x);
		s.close();
	}

}