Jawaban Jojo si Penulis 2

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
    String s1;
    Scanner masuk = new Scanner(System.in);
    s1 = masuk.nextLine();
        int x1=s1.length(),x2=x1/2;
    if (x1>20)
        {
            System.out.print("ERROR");
        }
        else if(s1.isEmpty())
        {
            System.out.print("KOSONG");
        }
        else if((x1%2)!=0)
        {
            s1 = s1.substring(0,x2) + "Ganjil" + s1.substring((x2+1),x1);
            System.out.print(s1);
        }
        else
        {
            s1 = s1.substring(0,(x2-1)) + "Genap" + s1.substring (x2+1,x1);
            s1 = s1.substring (0,s1.length()-1);
            int x = 20 - s1.length();
            for (int j=1; j<=x; j++)
            {
                s1 = " " + s1;
            }
            System.out.print(s1);
        }
    }
}