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

int main()
{
  char in[10001], s2[10001];
  int i, l, index, step, min;
  while (1)
  {
    scanf("%d\n", &step);
    if (!step) 
      return 0;

    gets(in);
 
    l = strlen(in);
/*    if (in[l-1] == '\n' || in[l-1] == '\r') in[--l] = '\0';
    if (in[l-1] == '\n' || in[l-1] == '\r') in[--l] = '\0';
*/
    index = 0;

    for (i = 0; i < l; i++)
    {
      in[i] = toupper(in[i]);
      if ((in[i] >= 'A' && in[i] <= 'Z')) 
        s2[index++] = in[i];
    }
    s2[index] = '\0';

    l = index;
    index = 0;
    min = 0;
    for (i = 0; i < l; i++)
    {
      in[i] = s2[index];
      index += (l/step+1);
      if (index >= l) 
        index = ++min;
    } 
    in[l] = '\0';

    printf("%s\n",in);
  }
  return 0;
}