
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Main main = new Main();
		main.run();
	}

	public void run() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		System.out.println(c(n)+c(m));
		sc.close();
	}

	private long c(int n) {
		if(n==0) return 0;
		return(n*(n-1))/2;
	}

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

	public static void main(String[] args) {
		Main main = new Main();
		main.run();
	}

	public void run() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		System.out.println(c(n)+c(m));
		sc.close();
	}

	private long c(int n) {
		if(n==0) return 0;
		return(n*(n-1))/2;
	}

} Main public static void main(String[] args) {
		Main main = new Main();
		main.run();
	} main {
		Main main = new Main();
		main.run();
	} Main main = new Main(); main new Main() main.run() main.run main String[] args args public void run() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		System.out.println(c(n)+c(m));
		sc.close();
	} run {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		System.out.println(c(n)+c(m));
		sc.close();
	} 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(c(n)+c(m)) System.out.println System.out System System.out c(n)+c(m) c(n) c n c(m) c m sc.close() sc.close sc private long c(int n) {
		if(n==0) return 0;
		return(n*(n-1))/2;
	} c {
		if(n==0) return 0;
		return(n*(n-1))/2;
	} if(n==0) return 0; n==0 n 0 return 0; 0 return(n*(n-1))/2; (n*(n-1))/2 (n*(n-1)) n (n-1) n 1 2 int n n public class Main {

	public static void main(String[] args) {
		Main main = new Main();
		main.run();
	}

	public void run() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		System.out.println(c(n)+c(m));
		sc.close();
	}

	private long c(int n) {
		if(n==0) return 0;
		return(n*(n-1))/2;
	}

} public class Main {

	public static void main(String[] args) {
		Main main = new Main();
		main.run();
	}

	public void run() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		System.out.println(c(n)+c(m));
		sc.close();
	}

	private long c(int n) {
		if(n==0) return 0;
		return(n*(n-1))/2;
	}

} Main

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Main main = new Main();
		main.run();
	}

	public void run() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		System.out.println(c(n)+c(m));
		sc.close();
	}

	private long c(int n) {
		if(n==0) return 0;
		return(n*(n-1))/2;
	}

}
