/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

import java.util.ArrayList;
import java.util.Locale;
import java.util.Scanner;
import java.util.StringTokenizer;

/**
 *
 * @author vaskol
 */
public class encipher {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
        
        String vstup1 = "";
        ArrayList<Integer> zoz1 = new ArrayList<Integer>();
        ArrayList<String> zoz2 = new ArrayList<String>();
        Scanner scan = new Scanner(System.in);
        String vstupCislo = scan.nextLine();
        while (vstupCislo.compareTo("0") != 0) {
            
            zoz1.add(Integer.parseInt(vstupCislo));
        
            String vstup = scan.nextLine();
            StringBuilder stringBuilder = new StringBuilder();
            for (StringTokenizer stringTokenizer = new StringTokenizer(vstup); stringTokenizer.hasMoreTokens();) {
                String token = stringTokenizer.nextToken();
                stringBuilder.append(token);
            }
            zoz2.add(stringBuilder.toString().toUpperCase());
            vstupCislo = scan.nextLine();
            
            
            
                       
        };
        
        
        for (int z = 0; z <zoz1.size(); z++) {
            StringBuilder stringBuilder = new StringBuilder();            
            int a = zoz1.get(z);
            int i = 0;
            int pom = 0;
            String veta = zoz2.get(z).toString();
            if(veta.length()>a){
            Character [] vetaP = new Character[veta.length()];
            
            for (int j = 0; j < veta.length(); j++) {
                if(i>=veta.length()) {pom += 1 ; i=pom; }  
//                System.out.print(veta.charAt(j));
                vetaP[i] =  veta.charAt(j);
//                stringBuilder.setCharAt(i, veta.charAt(j)) ;  
                i+=a;
                              
            }
            for (Character character : vetaP) {
                stringBuilder.append(character);
            }
            
           System.out.print(stringBuilder); }
            else {System.out.print(veta);};
            
        }
        
                
                }
}