#include <stdio.h>
#include <string>
#include <ctype.h>
#include <iostream>

using namespace std;

int main (void)
{
	int repetition;
	int spacesCounter = 0;
	string message;
	while (1)
	{
		scanf ("%d", &repetition);
		cin.get();
		if (!repetition)
		{
			break;	
		}
		getline (cin,message);
		for (unsigned int i=0; i<message.size(); i++)
		{
			if (message[i] == ' ')
			{
				spacesCounter++;	
			}
		}
		//cout << "length & message: " << repetition << " " << message << endl; 
		cout << "string size: " << message.size() << endl;
		//cout << "spaces counter: " << spacesCounter << endl;
		int length = message.size() - spacesCounter;
		char *encrypted = new char [length];
		if (repetition >= length) //vytlac cely text v kapitalkach
		{
			int j = 0;
			for (int i=0; i<length; i++)
			{
				if (message[j] == ' ')
				{
					j++;	
				}
				encrypted [i] = toupper (message[j++]);	
			}
		}
		else
		{
			int currentMessageIndex = 0;
			for (int i=0; i<repetition; i++)
			{
				for (int j=i; j<length; j+=repetition)
				{
					while (message[currentMessageIndex] == ' ')
					{
						currentMessageIndex++;	
					}
					encrypted [j] = toupper (message[currentMessageIndex++]);	
					//cout << "value: " << message[currentMessageIndex] << " position: " << j << endl;
				}
			}
		}
		for (int i=0; i<length; i++)
		{
			printf ("%c",encrypted[i]);	
		}
		printf ("\n");
		delete [] encrypted;
		repetition = spacesCounter = 0;
		message = "";
	}
	return (0);
}