import java.util.Scanner;
 
public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int N = input.nextInt();
		int M = input.nextInt();
		int cnt = 0;
		System.out.println(N*(N-1)/2+M*(M-1)/2);
	}
} import java.util.Scanner; Scanner java.util public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int N = input.nextInt();
		int M = input.nextInt();
		int cnt = 0;
		System.out.println(N*(N-1)/2+M*(M-1)/2);
	}
} Main public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int N = input.nextInt();
		int M = input.nextInt();
		int cnt = 0;
		System.out.println(N*(N-1)/2+M*(M-1)/2);
	} main {
		Scanner input = new Scanner(System.in);
		int N = input.nextInt();
		int M = input.nextInt();
		int cnt = 0;
		System.out.println(N*(N-1)/2+M*(M-1)/2);
	} Scanner input = new Scanner(System.in); input new Scanner(System.in) int N = input.nextInt(); N input.nextInt() input.nextInt input int M = input.nextInt(); M input.nextInt() input.nextInt input int cnt = 0; cnt 0 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 String[] args args public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int N = input.nextInt();
		int M = input.nextInt();
		int cnt = 0;
		System.out.println(N*(N-1)/2+M*(M-1)/2);
	}
} public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int N = input.nextInt();
		int M = input.nextInt();
		int cnt = 0;
		System.out.println(N*(N-1)/2+M*(M-1)/2);
	}
} Main
import java.util.Scanner;
 
public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int N = input.nextInt();
		int M = input.nextInt();
		int cnt = 0;
		System.out.println(N*(N-1)/2+M*(M-1)/2);
	}
}