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



import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import static java.lang.System.out;

/**
 *
 * @author cteam059
 */
public class encipher {

    public static void main(String args[]) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int count = Integer.parseInt(br.readLine());
        while(count != 0) {
            String text = br.readLine().toUpperCase();
            StringBuilder sb = new StringBuilder(text.length());
            for(int i = 0; i < text.length(); i++) {
                char ch = text.charAt(i);
                if(ch != ' ')
                    sb.append(ch);
            }
            text = sb.toString();
            int lenght = text.length();
            char[] result = new char[lenght];
            int level = 0;
            int lastPosition = 0;
            for(int i = 0; i < lenght; i ++) {
                result[lastPosition] = text.charAt(i);
                lastPosition += count;
                if(lastPosition >= lenght) {
                    lastPosition = ++level;
                }
                
            }
            out.println(new String(result));
            count = Integer.parseInt(br.readLine());
        }
    }
    

}