import java.util.Scanner;

public class Main {

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


	}

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

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


	}

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


	} main {
		Scanner scan = new Scanner(System.in);
		int n=scan.nextInt();
		int m=scan.nextInt();
		int[] a=new int[n+1];
		int[] b= new int[m];
		
		System.out.println((n*(n-1)/2)+(m*(m-1)/2));


	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int n=scan.nextInt(); n scan.nextInt() scan.nextInt scan int m=scan.nextInt(); m scan.nextInt() scan.nextInt scan int[] a=new int[n+1]; a new int[n+1] n+1 n 1 int[] b= new int[m]; b new int[m] m 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 scan = new Scanner(System.in);
		int n=scan.nextInt();
		int m=scan.nextInt();
		int[] a=new int[n+1];
		int[] b= new int[m];
		
		System.out.println((n*(n-1)/2)+(m*(m-1)/2));


	}

} public class Main {

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


	}

} Main
import java.util.Scanner;

public class Main {

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


	}

}
