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