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