/*
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 * and open the template in the editor.
 */


import java.util.Scanner;
/**
 *
 * @author louma
 */
public class encipher {
    public static void main(String[] args) {
        
        
        Scanner a = new Scanner(System.in);
        while (true)
        {
            String line = a.nextLine();
            if (line.equals("0") == true)
                break;
            
            short posun = Short.parseShort(line);
            String text = a.nextLine().replace(" ", "").toUpperCase();
            
            if (posun >= text.length())
            {
                System.out.println(text);
                continue;
            }
            
            char[] vystup = text.toCharArray();
            
            //System.out.printf("%d\n", text.length());
            
            int k = 0;
            for (int i = 0, j = 0; j < text.length(); i = (i + posun), j++)
            {
                if (i >= vystup.length)
                    i = ++k;
                
                //System.out.printf("%d -> %d\n", i, j);
                vystup[i] = text.charAt(j);
            }
            
            System.out.println(new String(vystup));
        }
    }
}