
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();

		int ans_n =( n * (n-1) ) / 2;
		int ans_m =( m * (m-1) ) / 2;

		System.out.println( ans_n + ans_m );

		sc.close();

	}

} 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();

		int ans_n =( n * (n-1) ) / 2;
		int ans_m =( m * (m-1) ) / 2;

		System.out.println( ans_n + ans_m );

		sc.close();

	}

} Main public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

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

		int ans_n =( n * (n-1) ) / 2;
		int ans_m =( m * (m-1) ) / 2;

		System.out.println( ans_n + ans_m );

		sc.close();

	} main {

		Scanner sc = new Scanner(System.in);

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

		int ans_n =( n * (n-1) ) / 2;
		int ans_m =( m * (m-1) ) / 2;

		System.out.println( ans_n + ans_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 int ans_n =( n * (n-1) ) / 2; ans_n ( n * (n-1) ) / 2 ( n * (n-1) ) n (n-1) n 1 2 int ans_m =( m * (m-1) ) / 2; ans_m ( m * (m-1) ) / 2 ( m * (m-1) ) m (m-1) m 1 2 System.out.println( ans_n + ans_m ) System.out.println System.out System System.out ans_n + ans_m ans_n ans_m sc.close() sc.close sc 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();

		int ans_n =( n * (n-1) ) / 2;
		int ans_m =( m * (m-1) ) / 2;

		System.out.println( ans_n + ans_m );

		sc.close();

	}

} public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

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

		int ans_n =( n * (n-1) ) / 2;
		int ans_m =( m * (m-1) ) / 2;

		System.out.println( ans_n + ans_m );

		sc.close();

	}

} 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();

		int ans_n =( n * (n-1) ) / 2;
		int ans_m =( m * (m-1) ) / 2;

		System.out.println( ans_n + ans_m );

		sc.close();

	}

}
