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 nans = n * (n-1) / 2;
    int mans = m * (m-1) / 2;
    int ans = nans + mans;
    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 nans = n * (n-1) / 2;
    int mans = m * (m-1) / 2;
    int ans = nans + mans;
    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 nans = n * (n-1) / 2;
    int mans = m * (m-1) / 2;
    int ans = nans + mans;
    System.out.println(ans);
  } main {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int m = sc.nextInt();
    int nans = n * (n-1) / 2;
    int mans = m * (m-1) / 2;
    int ans = nans + mans;
    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 nans = n * (n-1) / 2; nans n * (n-1) / 2 n * (n-1) n (n-1) n 1 2 int mans = m * (m-1) / 2; mans m * (m-1) / 2 m * (m-1) m (m-1) m 1 2 int ans = nans + mans; ans nans + mans nans mans 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 nans = n * (n-1) / 2;
    int mans = m * (m-1) / 2;
    int ans = nans + mans;
    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 nans = n * (n-1) / 2;
    int mans = m * (m-1) / 2;
    int ans = nans + mans;
    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 nans = n * (n-1) / 2;
    int mans = m * (m-1) / 2;
    int ans = nans + mans;
    System.out.println(ans);
  }
}