
import java.util.Scanner;


public class Main 
{
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int sum = 0;
        for(int i=1;i<n;i++)
        {
            sum+=i;
        }
        for(int i=1;i<m;i++)
        {
            sum+=i;
        }
        System.out.println(sum);
    }
} import java.util.Scanner; Scanner java.util public class Main 
{
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int sum = 0;
        for(int i=1;i<n;i++)
        {
            sum+=i;
        }
        for(int i=1;i<m;i++)
        {
            sum+=i;
        }
        System.out.println(sum);
    }
} Main public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int sum = 0;
        for(int i=1;i<n;i++)
        {
            sum+=i;
        }
        for(int i=1;i<m;i++)
        {
            sum+=i;
        }
        System.out.println(sum);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int sum = 0;
        for(int i=1;i<n;i++)
        {
            sum+=i;
        }
        for(int i=1;i<m;i++)
        {
            sum+=i;
        }
        System.out.println(sum);
    } 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 sum = 0; sum 0 for(int i=1;i<n;i++)
        {
            sum+=i;
        } int i=1; int i=1; i 1 i<n i n i++ i++ i {
            sum+=i;
        } {
            sum+=i;
        } sum+=i sum i for(int i=1;i<m;i++)
        {
            sum+=i;
        } int i=1; int i=1; i 1 i<m i m i++ i++ i {
            sum+=i;
        } {
            sum+=i;
        } sum+=i sum i System.out.println(sum) System.out.println System.out System System.out sum String[] args args public class Main 
{
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int sum = 0;
        for(int i=1;i<n;i++)
        {
            sum+=i;
        }
        for(int i=1;i<m;i++)
        {
            sum+=i;
        }
        System.out.println(sum);
    }
} public class Main 
{
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int sum = 0;
        for(int i=1;i<n;i++)
        {
            sum+=i;
        }
        for(int i=1;i<m;i++)
        {
            sum+=i;
        }
        System.out.println(sum);
    }
} Main

import java.util.Scanner;


public class Main 
{
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int sum = 0;
        for(int i=1;i<n;i++)
        {
            sum+=i;
        }
        for(int i=1;i<m;i++)
        {
            sum+=i;
        }
        System.out.println(sum);
    }
}
