#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXN 100000

char Buffer[MAXN];
char Input[MAXN];
char Output[MAXN];

char ToUpper(char c)
{
    if((c >= 'a') && (c <= 'z'))
    {
	return c + ('A' - 'a');
    }
    
    return c;
}

int main()
{
    while(1)
    {
	int n;
	scanf("%d", &n);
	
	if(!(n))
	{
	    break;
	}
	
	getchar();
	fgets(Buffer, MAXN, stdin);
	
	int l = 0;
	for(int i = 0; Buffer[i]; i++)
	{
	    if((Buffer[i] != ' ') && (Buffer[i] != '\n'))
	    {
		Input[l++] = Buffer[i];
	    }
	}
	
	int mod = 0, cur = 0;
	for(int i = 0; i < l; i++)
	{
	    Output[cur] = Input[i];
	    cur += n;
	    if(cur >= l)
	    {
		cur = ++mod;
	    }
	}
	
	for(int i = 0; i < l; i++)
	{
	    putchar(ToUpper(Output[i]));
	}
	
	/*int l = strlen(Buffer);
	for(int i = 0; i < n; i++)
	{
	    for(int j = i; j < l; j += n)
	    {
		if((Buffer[j] >= 'a') && (Buffer[j] <= 'z'))
		{
		    putchar(Buffer[j] + ('A' - 'a'));
		}
		else if((Buffer[j] >= 'A') && (Buffer[j] <= 'Z'))
		{
		    putchar(Buffer[j]);
		}
	    }
	}*/
	
	putchar('\n');
    }
    
    return 0;
}