import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.ZoneId;

public class Main {
	public static void main(String[] args) {
		String strDate = "2021-11-25";
		String strTime = "15:20";
		LocalDateTime ldt = LocalDateTime.of(LocalDate.parse(strDate), LocalTime.parse(strTime));
		Instant instant = ldt.toInstant(ZoneId.systemDefault().getRules().getOffset(ldt));
		System.out.println(instant);
	}
}