#include <stdio.h>
#include <stdlib.h>
#include <sstream>
#include <iostream>

using namespace std;

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

int main() {
  /*	while (cin) {
	  string line;
	  getline(cin,line);
	  int n=15;
	  string result;
	  int linelen = line.size();
	  while (result.size()!=linelen) {
	    string temp;
	    for (int i=0; i<line.size(); i++) {
	      if (i % n == 0) {
		result += line[i];
	      } else {
		temp += line[i];
	      }
	    }
	    line = temp;
	    n -= 1;
	    cout << result << endl;
	  }
	}
  */
  	while (cin) {
	  int n;
	  string rawtext;
	  cin >> n;
	  if (n==0) return 0;
	  getline(cin,rawtext);
	  getline(cin,rawtext);
	  stringstream text;
	  for (int i=0; i<rawtext.size(); i++) {
	    if (rawtext[i] != ' ') {
	      text << upcase(rawtext[i]);
	    }
	  }
	  string t = text.str();
	  string target_str = t;
	  
	  int cnt_orig=0;
	  for (int begin=0; begin<n; begin++) {
	    for (int i=begin; i<t.size(); i+=n) {
	      target_str[i] = t[cnt_orig];
	      cnt_orig++;
	    }
	  }
	  cout << target_str << endl;

	}
	return 0;
}