import java.util.*;

public class Main {
    static int xC2(int x){
        int A;
        if(x>1)
            A= x*(x-1)/2;
        else
            A = 0;
        
        return A;
        }
    public static void main(String[] args){
        Scanner stdIn = new Scanner(System.in);
        int N = stdIn.nextInt();
        int M = stdIn.nextInt();

        int E = 0;
        E = xC2(N) + xC2(M);

        System.out.print(E);



    }
}
/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