import static java.lang.System.out;

import java.time.DayOfWeek;
import java.time.YearMonth;
import java.time.ZoneId;

public class Main {
	public static void main(String[] args) {
		DayOfWeek dow = getFirstDayOfMonth(2021, 5, ZoneId.of("America/Los_Angeles"));
		out.println(dow); // SATURDAY
	}

	private static DayOfWeek getFirstDayOfMonth(int year, int month, ZoneId zoneId) {
		return YearMonth.of(year, month)
						.atDay(1)
						.atStartOfDay(zoneId)
						.getDayOfWeek();
	}
}