import 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());
		System.out.println((n * (n - 1) / 2) + m * (m - 1) / 2);
	}
} import java.util.*; util.* java 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());
		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 = Integer.parseInt(sc.next());
		int m = Integer.parseInt(sc.next());
		System.out.println((n * (n - 1) / 2) + m * (m - 1) / 2);
	} main {
		Scanner sc = new Scanner(System.in);
		int n = Integer.parseInt(sc.next());
		int m = Integer.parseInt(sc.next());
		System.out.println((n * (n - 1) / 2) + m * (m - 1) / 2);
	} 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 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());
		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 = Integer.parseInt(sc.next());
		int m = Integer.parseInt(sc.next());
		System.out.println((n * (n - 1) / 2) + m * (m - 1) / 2);
	}
} Main
import 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());
		System.out.println((n * (n - 1) / 2) + m * (m - 1) / 2);
	}
}