import 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(n*(n-1)/2+m*(m-1)/2);
    }
    if (n>1&&m<2) {
      System.out.println(n*(n-1)/2);
    }
    if (n<2&&m>1) {
      System.out.println(m*(m-1)/2);
    }
    if (n<2&&m<2) {
      System.out.println(0);
    }
  }
} import java.util.*; util.* java 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(n*(n-1)/2+m*(m-1)/2);
    }
    if (n>1&&m<2) {
      System.out.println(n*(n-1)/2);
    }
    if (n<2&&m>1) {
      System.out.println(m*(m-1)/2);
    }
    if (n<2&&m<2) {
      System.out.println(0);
    }
  }
} 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(n*(n-1)/2+m*(m-1)/2);
    }
    if (n>1&&m<2) {
      System.out.println(n*(n-1)/2);
    }
    if (n<2&&m>1) {
      System.out.println(m*(m-1)/2);
    }
    if (n<2&&m<2) {
      System.out.println(0);
    }
  } main {
    Scanner sc=new Scanner(System.in);
    int n=sc.nextInt();
    int m=sc.nextInt();

    if (n>1&&m>1) {
      System.out.println(n*(n-1)/2+m*(m-1)/2);
    }
    if (n>1&&m<2) {
      System.out.println(n*(n-1)/2);
    }
    if (n<2&&m>1) {
      System.out.println(m*(m-1)/2);
    }
    if (n<2&&m<2) {
      System.out.println(0);
    }
  } 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(n*(n-1)/2+m*(m-1)/2);
    } n>1&&m>1 n>1 n 1 m>1 m 1 {
      System.out.println(n*(n-1)/2+m*(m-1)/2);
    } System.out.println(n*(n-1)/2+m*(m-1)/2) System.out.println System.out System System.out n*(n-1)/2+m*(m-1)/2 n*(n-1)/2 n*(n-1) n (n-1) n 1 2 m*(m-1)/2 m*(m-1) m (m-1) m 1 2 if (n>1&&m<2) {
      System.out.println(n*(n-1)/2);
    } n>1&&m<2 n>1 n 1 m<2 m 2 {
      System.out.println(n*(n-1)/2);
    } System.out.println(n*(n-1)/2) System.out.println System.out System System.out n*(n-1)/2 n*(n-1) n (n-1) n 1 2 if (n<2&&m>1) {
      System.out.println(m*(m-1)/2);
    } n<2&&m>1 n<2 n 2 m>1 m 1 {
      System.out.println(m*(m-1)/2);
    } System.out.println(m*(m-1)/2) System.out.println System.out System System.out m*(m-1)/2 m*(m-1) m (m-1) m 1 2 if (n<2&&m<2) {
      System.out.println(0);
    } n<2&&m<2 n<2 n 2 m<2 m 2 {
      System.out.println(0);
    } System.out.println(0) System.out.println System.out System System.out 0 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(n*(n-1)/2+m*(m-1)/2);
    }
    if (n>1&&m<2) {
      System.out.println(n*(n-1)/2);
    }
    if (n<2&&m>1) {
      System.out.println(m*(m-1)/2);
    }
    if (n<2&&m<2) {
      System.out.println(0);
    }
  }
} 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(n*(n-1)/2+m*(m-1)/2);
    }
    if (n>1&&m<2) {
      System.out.println(n*(n-1)/2);
    }
    if (n<2&&m>1) {
      System.out.println(m*(m-1)/2);
    }
    if (n<2&&m<2) {
      System.out.println(0);
    }
  }
} Main
import 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(n*(n-1)/2+m*(m-1)/2);
    }
    if (n>1&&m<2) {
      System.out.println(n*(n-1)/2);
    }
    if (n<2&&m>1) {
      System.out.println(m*(m-1)/2);
    }
    if (n<2&&m<2) {
      System.out.println(0);
    }
  }
}
