import java.io.*;
import java.util.*;


public class Main {
    public static void main (String[]args)throws IOException {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        System.out.println((N*(N-1)+(M*(M-1)))/2);
    }
} import java.io.*; io.* java import java.util.*; util.* java public class Main {
    public static void main (String[]args)throws IOException {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        System.out.println((N*(N-1)+(M*(M-1)))/2);
    }
} Main public static void main (String[]args)throws IOException {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        System.out.println((N*(N-1)+(M*(M-1)))/2);
    } main {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        System.out.println((N*(N-1)+(M*(M-1)))/2);
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int N = scanner.nextInt(); N scanner.nextInt() scanner.nextInt scanner int M = scanner.nextInt(); M scanner.nextInt() scanner.nextInt scanner System.out.println((N*(N-1)+(M*(M-1)))/2) System.out.println System.out System System.out (N*(N-1)+(M*(M-1)))/2 (N*(N-1)+(M*(M-1))) N*(N-1) N (N-1) N 1 (M*(M-1)) M (M-1) M 1 2 String[]args args public class Main {
    public static void main (String[]args)throws IOException {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        System.out.println((N*(N-1)+(M*(M-1)))/2);
    }
} public class Main {
    public static void main (String[]args)throws IOException {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        System.out.println((N*(N-1)+(M*(M-1)))/2);
    }
} Main
import java.io.*;
import java.util.*;


public class Main {
    public static void main (String[]args)throws IOException {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        System.out.println((N*(N-1)+(M*(M-1)))/2);
    }
}
