UVA - 11192 - Group Reverse

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws IOException {
       BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       StringBuilder sb = new StringBuilder();
       while(true){
           StringTokenizer st=new StringTokenizer(br.readLine());
           int n=Integer.parseInt(st.nextToken());
           if(n==0){
               break;
           }
           String temp=st.nextToken();
           int length=temp.length()/n;
           StringBuilder str=new StringBuilder();
           for(int i=0,j=0;i<temp.length();i++){
               str.append(temp.charAt(i));
               if(j%length==length-1){
                   j=0;
                   sb.append(str.reverse());
                   str=new StringBuilder();
               }else{
                   j++;
               }
           }
           sb.append("\n");
       }
       System.out.print(sb);
    }
  
}