import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.Scanner;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author cteam063
 */
public class encipher {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        String message;
        int j, cur;

        while (n != 0) {
            message = readLine().trim();
            message = removeSpaces(message);

            char[] ret = new char[message.length()];
            cur = 0;

            for (int i = 0; i < n; i++) {
                j = i;
                while (j < ret.length) {
                    ret[j] = message.charAt(cur);
                    cur++;
                    j += n;
                }
            }

            System.out.println(String.valueOf(ret));

            n = scanner.nextInt();
        }
    }

    public static String removeSpaces(String message) {
        StringBuilder str = new StringBuilder();
        String[] words = message.split(" ");
        for (String word : words) {
            str.append(word.trim().toUpperCase());
        }
        return str.toString();
    }

    public static String readLine() {
        String ret = "";
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            ret = reader.readLine();
        } catch (IOException ex) {
        }
        return ret;
    }
}