
import java.util.Scanner;
public class Main {

	@SuppressWarnings("resource")
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int M=sc.nextInt();
		System.out.println(calcNumOfCombination(N, 2)+calcNumOfCombination(M, 2));

		}
	 public static int calcNumOfCombination(int n, int r){
	        int num = 1;
	        for(int i = 1; i <= r; i++){
	            num = num * (n - i + 1) / i;
	        }
	        return num;
	    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz