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

using namespace std;

char vystup[20000];

int main(){
    int klic, delka, pocet, stupen;
    string vstup, tmp = "";
    
    
    while(1){
	cin >> klic;
	if(klic == 0) break;
	cin.get();
	getline(cin, vstup);
	tmp = "";
	delka = vstup.length();
	for(int i=0;i<delka;i++){
	    if(isalpha(vstup[i])){
		tmp += toupper(vstup[i]);
	    }
	}
	
	delka = tmp.length();
	pocet = 0;
	stupen = 0;
	
	while(pocet < delka){
	    for(int i=stupen;i<delka;i+= klic){
		//cout << tmp[i] << endl;
		
		vystup[i] = tmp[pocet];
		pocet++;
	    }
	    
	    stupen++;
	}
	
	for(int i=0;i<pocet;i++){
	    cout << vystup[i];
	}
	cout << endl;
    
    }

    return 0;
}