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;

		if (N >= 2) {
			ans += (N * (N-1)) /2;
		}
		if (M >= 2) {
			ans += (M * (M-1)) /2;
		}

		System.out.println(ans);

	}
} 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;

		if (N >= 2) {
			ans += (N * (N-1)) /2;
		}
		if (M >= 2) {
			ans += (M * (M-1)) /2;
		}

		System.out.println(ans);

	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		int M = sc.nextInt();
		int ans = 0;

		if (N >= 2) {
			ans += (N * (N-1)) /2;
		}
		if (M >= 2) {
			ans += (M * (M-1)) /2;
		}

		System.out.println(ans);

	} main {
		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		int M = sc.nextInt();
		int ans = 0;

		if (N >= 2) {
			ans += (N * (N-1)) /2;
		}
		if (M >= 2) {
			ans += (M * (M-1)) /2;
		}

		System.out.println(ans);

	} 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 if (N >= 2) {
			ans += (N * (N-1)) /2;
		} N >= 2 N 2 {
			ans += (N * (N-1)) /2;
		} ans += (N * (N-1)) /2 ans (N * (N-1)) /2 (N * (N-1)) N (N-1) N 1 2 if (M >= 2) {
			ans += (M * (M-1)) /2;
		} M >= 2 M 2 {
			ans += (M * (M-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 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;

		if (N >= 2) {
			ans += (N * (N-1)) /2;
		}
		if (M >= 2) {
			ans += (M * (M-1)) /2;
		}

		System.out.println(ans);

	}
} 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;

		if (N >= 2) {
			ans += (N * (N-1)) /2;
		}
		if (M >= 2) {
			ans += (M * (M-1)) /2;
		}

		System.out.println(ans);

	}
} 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;

		if (N >= 2) {
			ans += (N * (N-1)) /2;
		}
		if (M >= 2) {
			ans += (M * (M-1)) /2;
		}

		System.out.println(ans);

	}
}