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