利用LocalDate 类自带的方法

import java.util.Scanner;
import java.time.LocalDate;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.nextLine();
        String[] ss = s.split(" ");
        int yy = Integer.valueOf(ss[0]);
        int mon = Integer.valueOf(ss[1]);
        int dd = Integer.valueOf(ss[2]);
        LocalDate ld = LocalDate.of(yy,mon,dd);
        System.out.print(ld.getDayOfYear());
    }
}