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();
	}
}

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