import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = 0;
		int M = 0;
		N = sc.nextInt();
		M = sc.nextInt();
		int ans = 0;
		ans = N * (N - 1) / 2 + M * (M - 1) / 2;
		System.out.println(ans);
		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 = 0;
		int M = 0;
		N = sc.nextInt();
		M = sc.nextInt();
		int ans = 0;
		ans = N * (N - 1) / 2 + M * (M - 1) / 2;
		System.out.println(ans);
		sc.close();
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = 0;
		int M = 0;
		N = sc.nextInt();
		M = sc.nextInt();
		int ans = 0;
		ans = N * (N - 1) / 2 + M * (M - 1) / 2;
		System.out.println(ans);
		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);
		int N = 0;
		int M = 0;
		N = sc.nextInt();
		M = sc.nextInt();
		int ans = 0;
		ans = N * (N - 1) / 2 + M * (M - 1) / 2;
		System.out.println(ans);
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = 0; N 0 int M = 0; M 0 N = sc.nextInt() N sc.nextInt() sc.nextInt sc M = sc.nextInt() M sc.nextInt() sc.nextInt sc int ans = 0; ans 0 ans = N * (N - 1) / 2 + M * (M - 1) / 2 ans 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(ans) System.out.println System.out System System.out ans 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 = 0;
		int M = 0;
		N = sc.nextInt();
		M = sc.nextInt();
		int ans = 0;
		ans = N * (N - 1) / 2 + M * (M - 1) / 2;
		System.out.println(ans);
		sc.close();
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = 0;
		int M = 0;
		N = sc.nextInt();
		M = sc.nextInt();
		int ans = 0;
		ans = N * (N - 1) / 2 + M * (M - 1) / 2;
		System.out.println(ans);
		sc.close();
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = 0;
		int M = 0;
		N = sc.nextInt();
		M = sc.nextInt();
		int ans = 0;
		ans = N * (N - 1) / 2 + M * (M - 1) / 2;
		System.out.println(ans);
		sc.close();
	}

}