Somebody can explain to me how this code is working?

public class Solution {

    public static int even;
    public static int odd;

    public static void main(String[] args) throws IOException {
        //write your code here
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        int a = Integer.parseInt(reader.readLine());
        System.out.println("Value of a is '" + a + "'. Now entering loop");
        while (a > 0) {
            System.out.println("New loop cycle a = '" + a + "' which is greater than 0");
            int remainder = a % 10;
            System.out.print("\ta % 10 = '" + remainder + "' which is an");
            if (a % 2 == 0) {
                even++;
                System.out.println(" even number. Even digits now equals '" + even + "'");
            }
            else{
                odd++;
                System.out.println(" even number. Even digits now equals '" + even + "'");
            }
            a = a / 10;
            System.out.println("\tSetting a to a divided by 10, which equals '" + a + "'");
        }
        System.out.println("exiting loop");
        System.out.println("Even: " + even);
        System.out.println("Odd: " + odd);
    }
}