PAT乙級-寫出這個數

package 寫出這個數;
import java.util.Scanner;
public class Main {
public static void main(String[] args)
{
Scanner s=new Scanner(System.in);
String str=s.next();
int len=str.length(); 
String[] a={"ling","yi","er","san","si","wu","liu","qi","ba","jiu"};
int sum=0;
for(int i=0;i<len;i++)
{
sum=sum+(str.charAt(i)-48);
}

String str1=sum+"";
int len1=str1.length();
for(int i=0;i<len1-1;i++)
{
System.out.print(a[(str1.charAt(i)-48)]+" ");
}
System.out.print(a[str1.charAt(len1-1)-48]);
}
}