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();

    if (n == 1 && m == 1) {
      System.out.println(0);
      return;
    }

    int nSum = n > 1 ? (n * (n - 1)) / 2 : 0;
    int mSum = m > 1 ? (m * (m - 1)) / 2 : 0;
    System.out.println(nSum + mSum);
  }
} 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();

    if (n == 1 && m == 1) {
      System.out.println(0);
      return;
    }

    int nSum = n > 1 ? (n * (n - 1)) / 2 : 0;
    int mSum = m > 1 ? (m * (m - 1)) / 2 : 0;
    System.out.println(nSum + mSum);
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    int m = sc.nextInt();

    if (n == 1 && m == 1) {
      System.out.println(0);
      return;
    }

    int nSum = n > 1 ? (n * (n - 1)) / 2 : 0;
    int mSum = m > 1 ? (m * (m - 1)) / 2 : 0;
    System.out.println(nSum + mSum);
  } main {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    int m = sc.nextInt();

    if (n == 1 && m == 1) {
      System.out.println(0);
      return;
    }

    int nSum = n > 1 ? (n * (n - 1)) / 2 : 0;
    int mSum = m > 1 ? (m * (m - 1)) / 2 : 0;
    System.out.println(nSum + mSum);
  } 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 if (n == 1 && m == 1) {
      System.out.println(0);
      return;
    } n == 1 && m == 1 n == 1 n 1 m == 1 m 1 {
      System.out.println(0);
      return;
    } System.out.println(0) System.out.println System.out System System.out 0 return; int nSum = n > 1 ? (n * (n - 1)) / 2 : 0; nSum n > 1 ? (n * (n - 1)) / 2 : 0 n > 1 n 1 (n * (n - 1)) / 2 (n * (n - 1)) n (n - 1) n 1 2 0 int mSum = m > 1 ? (m * (m - 1)) / 2 : 0; mSum m > 1 ? (m * (m - 1)) / 2 : 0 m > 1 m 1 (m * (m - 1)) / 2 (m * (m - 1)) m (m - 1) m 1 2 0 System.out.println(nSum + mSum) System.out.println System.out System System.out nSum + mSum nSum mSum 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();

    if (n == 1 && m == 1) {
      System.out.println(0);
      return;
    }

    int nSum = n > 1 ? (n * (n - 1)) / 2 : 0;
    int mSum = m > 1 ? (m * (m - 1)) / 2 : 0;
    System.out.println(nSum + mSum);
  }
} public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    int m = sc.nextInt();

    if (n == 1 && m == 1) {
      System.out.println(0);
      return;
    }

    int nSum = n > 1 ? (n * (n - 1)) / 2 : 0;
    int mSum = m > 1 ? (m * (m - 1)) / 2 : 0;
    System.out.println(nSum + mSum);
  }
} 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();

    if (n == 1 && m == 1) {
      System.out.println(0);
      return;
    }

    int nSum = n > 1 ? (n * (n - 1)) / 2 : 0;
    int mSum = m > 1 ? (m * (m - 1)) / 2 : 0;
    System.out.println(nSum + mSum);
  }
}
