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

        int count = 0;
        for(int i = 0; i<n; i++){
            for(int j = i + 1; j<n; j++){
                count++;
            }
        }
        for(int i = 0; i<m; i++){
            for(int j = i + 1; j<m; j++){
                count++;
            }
        }
        System.out.println(count);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();

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

        int count = 0;
        for(int i = 0; i<n; i++){
            for(int j = i + 1; j<n; j++){
                count++;
            }
        }
        for(int i = 0; i<m; i++){
            for(int j = i + 1; j<m; j++){
                count++;
            }
        }
        System.out.println(count);
    }
} 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 count = 0;
        for(int i = 0; i<n; i++){
            for(int j = i + 1; j<n; j++){
                count++;
            }
        }
        for(int i = 0; i<m; i++){
            for(int j = i + 1; j<m; j++){
                count++;
            }
        }
        System.out.println(count);
    }
}