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