//package solution;

import java.io.*;
import java.util.*;
import java.math.*;
import java.awt.Point;

public final class Main {
    BufferedReader br;
    StringTokenizer stk;

    public static void main(String[] args) throws Exception {
        new Main().run();
    }
    
    {
        stk = null;
        br = new BufferedReader(new InputStreamReader(System.in));
    }
    
    void run() throws Exception {
        int n = ni(), m = ni();
        int pairs = ((n * (n - 1)) / 2) + ((m * (m - 1)) / 2);
        pl(pairs);
    }
    
    //Reader & Writer
    String nextToken() throws Exception {
        if (stk == null || !stk.hasMoreTokens()) {
            stk = new StringTokenizer(br.readLine(), " ");
        }
        return stk.nextToken();
    }

    String nt() throws Exception {
        return nextToken();
    }

    String ns() throws Exception {
        return br.readLine();
    }

    int ni() throws Exception {
        return Integer.parseInt(nextToken());
    }

    long nl() throws Exception {
        return Long.parseLong(nextToken());
    }

    double nd() throws Exception {
        return Double.parseDouble(nextToken());
    }

    void p(Object o) {
        System.out.print(o);
    }

    void pl(Object o) {
        System.out.println(o);
    }
    
    void selector() {
        Random rd = new Random();
        String[] s = new String[] {"Strings", "Sorting", "Search"
                , "Graph theory", "Greedy", "Dynamic programming"
                , "Constructive algos", "Bit manipulation", "Recursion"};
        pl(s[rd.nextInt(s.length)] + " " + (rd.nextInt(5)+1));
    }
}
/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