import java.util.Scanner;

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

        for (int i = 0; i < m + n; i++) {
            for (int j = i; j < m + n; j++) {
                if (!(i == j) && (array[i] + array[j]) % 2 == 0) {
                    count++;
                }
            }
        }
        System.out.println(count);
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz