Days in a Month (switch with yield)

/*
 * Problem : Find the number of days.
 * Input   : Month and year.
 * Output  : The number of days.
 * Approach: If statements.
 * Time    : O(1)
 * Space   : O(1)
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
    // This method solves the task. It receives the input and returns the answer.
    static int solve(long a, long b) {
        // Step 1: February depends on the year. Other months have a fixed length.
        int month = (int) a;
        long year = b;
        if (month == 2) {
            boolean leap = (year % 4 == 0 && year % 100 != 0) || year % 400 == 0;
            return leap ? 29 : 28;
        }
        // Step 2: April, June, September and November have 30 days. All other months have 31.
        if (month == 4 || month == 6 || month == 9 || month == 11) {
            return 30;
        }
        return 31;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long a = scanner.nextLong();
        long b = scanner.nextLong();
        System.out.println(solve(a, b));
    }
}