import java.math.*;
import java.util.*;

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