import java.io.*;
import java.util.*;

public class encipher {

    StringTokenizer st = new StringTokenizer("");
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    public static void main(String[] args) throws Exception {
        encipher inst = new encipher();
        while (inst.run()) {
        }
    }

    public boolean run() throws Exception {
        int step = nextInt();
        if(step==0) return false;
        String plainText = br.readLine();
        StringBuilder cipherText = new StringBuilder();
        plainText = plainText.replaceAll(" ", "");
        plainText = plainText.toUpperCase();
        int strSize = plainText.length();
        int lenght = strSize / step;
        if((strSize % step)>0) lenght++;
        for(int i = 0; i < lenght; i++) {
            for(int j = i; j < strSize; j+=lenght) {
                cipherText.append(plainText.charAt(j));
            }
        }
        System.out.println(cipherText.toString());
        return true;
    }

    public String nextToken() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }

    public int nextInt() throws Exception {
        return Integer.parseInt(nextToken());
    }

    public double nextDouble() throws Exception {
        return Double.parseDouble(nextToken());
    }
}