import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        
        long ans = 0;
        if(n >= 2){
            ans += (n * (n-1)) / 2;
        }
        if(m >= 2){
            ans += (m * (m-1)) / 2;
        }
        System.out.println(ans);
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        
        long ans = 0;
        if(n >= 2){
            ans += (n * (n-1)) / 2;
        }
        if(m >= 2){
            ans += (m * (m-1)) / 2;
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) {
        
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        
        long ans = 0;
        if(n >= 2){
            ans += (n * (n-1)) / 2;
        }
        if(m >= 2){
            ans += (m * (m-1)) / 2;
        }
        System.out.println(ans);
    } main {
        
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        
        long ans = 0;
        if(n >= 2){
            ans += (n * (n-1)) / 2;
        }
        if(m >= 2){
            ans += (m * (m-1)) / 2;
        }
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = Integer.parseInt(sc.next()); n Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int m = Integer.parseInt(sc.next()); m Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc long ans = 0; ans 0 if(n >= 2){
            ans += (n * (n-1)) / 2;
        } n >= 2 n 2 {
            ans += (n * (n-1)) / 2;
        } ans += (n * (n-1)) / 2 ans (n * (n-1)) / 2 (n * (n-1)) n (n-1) n 1 2 if(m >= 2){
            ans += (m * (m-1)) / 2;
        } m >= 2 m 2 {
            ans += (m * (m-1)) / 2;
        } ans += (m * (m-1)) / 2 ans (m * (m-1)) / 2 (m * (m-1)) m (m-1) m 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) {
        
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        
        long ans = 0;
        if(n >= 2){
            ans += (n * (n-1)) / 2;
        }
        if(m >= 2){
            ans += (m * (m-1)) / 2;
        }
        System.out.println(ans);
    }
} public class Main {

    public static void main(String[] args) {
        
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        
        long ans = 0;
        if(n >= 2){
            ans += (n * (n-1)) / 2;
        }
        if(m >= 2){
            ans += (m * (m-1)) / 2;
        }
        System.out.println(ans);
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        
        long ans = 0;
        if(n >= 2){
            ans += (n * (n-1)) / 2;
        }
        if(m >= 2){
            ans += (m * (m-1)) / 2;
        }
        System.out.println(ans);
    }
}