import java.util.*;
import java.io.*;
import java.math.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int ans = even*(even-1)/2 + odd*(odd-1)/2;
        System.out.println(ans);
    }

} import java.util.*; util.* java import java.io.*; io.* java import java.math.*; math.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int ans = even*(even-1)/2 + odd*(odd-1)/2;
        System.out.println(ans);
    }

} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int ans = even*(even-1)/2 + odd*(odd-1)/2;
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int ans = even*(even-1)/2 + odd*(odd-1)/2;
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int even = sc.nextInt(); even sc.nextInt() sc.nextInt sc int odd = sc.nextInt(); odd sc.nextInt() sc.nextInt sc int ans = even*(even-1)/2 + odd*(odd-1)/2; ans even*(even-1)/2 + odd*(odd-1)/2 even*(even-1)/2 even*(even-1) even (even-1) even 1 2 odd*(odd-1)/2 odd*(odd-1) odd (odd-1) odd 1 2 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int ans = even*(even-1)/2 + odd*(odd-1)/2;
        System.out.println(ans);
    }

} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int ans = even*(even-1)/2 + odd*(odd-1)/2;
        System.out.println(ans);
    }

} Main
import java.util.*;
import java.io.*;
import java.math.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int even = sc.nextInt();
        int odd = sc.nextInt();
        int ans = even*(even-1)/2 + odd*(odd-1)/2;
        System.out.println(ans);
    }

}