import java.util.Scanner;
class Main{
	public static void main(String[] args){
    	Scanner console = new Scanner(System.in);
    	int N = console.nextInt();
      int M = console.nextInt();
      System.out.println(combination(N) + combination(M));
	}
	
	public static int combination(int num){
	   int comb = 0;
      int temp = 1;
      for(int i = num; i > num - 2; i--){
         temp *= i;
      }
      temp /= 2;
      if(temp != 0){
         comb = temp;
     	}
     	return comb;
	}
}
/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