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