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 ans = 0;

		//偶数＋偶数
		ans += N * (N - 1) / 2;
		
		//奇数＋奇数
		ans += M * (M - 1) / 2;
		
		System.out.println(ans);
		sc.close();
	}
	
} 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 ans = 0;

		//偶数＋偶数
		ans += N * (N - 1) / 2;
		
		//奇数＋奇数
		ans += M * (M - 1) / 2;
		
		System.out.println(ans);
		sc.close();
	}
	
} Main public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int M = sc.nextInt();
		int ans = 0;

		//偶数＋偶数
		ans += N * (N - 1) / 2;
		
		//奇数＋奇数
		ans += M * (M - 1) / 2;
		
		System.out.println(ans);
		sc.close();
	} main {
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int M = sc.nextInt();
		int ans = 0;

		//偶数＋偶数
		ans += N * (N - 1) / 2;
		
		//奇数＋奇数
		ans += M * (M - 1) / 2;
		
		System.out.println(ans);
		sc.close();
	} 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 ans = 0; ans 0 ans += N * (N - 1) / 2 ans N * (N - 1) / 2 N * (N - 1) N (N - 1) N 1 2 ans += M * (M - 1) / 2 ans M * (M - 1) / 2 M * (M - 1) M (M - 1) M 1 2 System.out.println(ans) System.out.println System.out System System.out ans sc.close() sc.close sc 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 ans = 0;

		//偶数＋偶数
		ans += N * (N - 1) / 2;
		
		//奇数＋奇数
		ans += M * (M - 1) / 2;
		
		System.out.println(ans);
		sc.close();
	}
	
} public class Main {
 
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int M = sc.nextInt();
		int ans = 0;

		//偶数＋偶数
		ans += N * (N - 1) / 2;
		
		//奇数＋奇数
		ans += M * (M - 1) / 2;
		
		System.out.println(ans);
		sc.close();
	}
	
} 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 ans = 0;

		//偶数＋偶数
		ans += N * (N - 1) / 2;
		
		//奇数＋奇数
		ans += M * (M - 1) / 2;
		
		System.out.println(ans);
		sc.close();
	}
	
}