import 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 = 0;
		if(n >= 2){
			ans += n * (n - 1) / 2;
		}
		if(m >= 2){
			ans += m * (m - 1) / 2;
		}
		System.out.println(ans);
	}
} import java.util.*; util.* java 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 = 0;
		if(n >= 2){
			ans += n * (n - 1) / 2;
		}
		if(m >= 2){
			ans += m * (m - 1) / 2;
		}
		System.out.println(ans);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int ans = 0;
		if(n >= 2){
			ans += n * (n - 1) / 2;
		}
		if(m >= 2){
			ans += m * (m - 1) / 2;
		}
		System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int ans = 0;
		if(n >= 2){
			ans += n * (n - 1) / 2;
		}
		if(m >= 2){
			ans += m * (m - 1) / 2;
		}
		System.out.println(ans);
	} 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 = 0; ans 0 if(n >= 2){
			ans += n * (n - 1) / 2;
		} n >= 2 n 2 {
			ans += n * (n - 1) / 2;
		} ans += n * (n - 1) / 2 ans n * (n - 1) / 2 n * (n - 1) n (n - 1) n 1 2 if(m >= 2){
			ans += m * (m - 1) / 2;
		} m >= 2 m 2 {
			ans += m * (m - 1) / 2;
		} ans += m * (m - 1) / 2 ans 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 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 = 0;
		if(n >= 2){
			ans += n * (n - 1) / 2;
		}
		if(m >= 2){
			ans += m * (m - 1) / 2;
		}
		System.out.println(ans);
	}
} 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 = 0;
		if(n >= 2){
			ans += n * (n - 1) / 2;
		}
		if(m >= 2){
			ans += m * (m - 1) / 2;
		}
		System.out.println(ans);
	}
} Main
import 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 = 0;
		if(n >= 2){
			ans += n * (n - 1) / 2;
		}
		if(m >= 2){
			ans += m * (m - 1) / 2;
		}
		System.out.println(ans);
	}
}