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