import java.util.*;

public class encipher
{
    public static void main(String[] args)
    {
	Scanner sc = new Scanner(System.in);
	
	int n = 0;
	n = sc.nextInt();
	while(n != 0)
	{
	    sc.nextLine();
	    String line = sc.	nextLine();
	    line = line.replace(" ","").toUpperCase();
	    //System.out.println(line);
	    String[] pole = new String[n];
	    int iod, ido;
	    iod = 0;
	    
	    for(int i = 0; i < n; i++)
	    {
		ido = iod + line.length()/n;
		if(line.length()%n-i > 0) ido++;
		
		pole[i] = line.substring(iod,ido);
		//System.out.println(pole[i]);
		iod = ido;
	    }
	    StringBuilder sb = new StringBuilder();
	    Boolean ok;
	    int prvek = -1;
	    do
	    {
		prvek++;
		ok = true;
		for(int i = 0; i<n; i++)
		{
		    if(pole[i].length()>prvek)
		    {
			sb.append(pole[i].substring(prvek,prvek+1));
			
		    } else {ok = false;}
		}
	    } while(ok);
	    System.out.println(sb.toString());
	    n = sc.nextInt();
	}
    }
}