#include <iostream>
#include <string>
int main(){
//std::cout << "yep" << std::endl;
std::string message;
while (true){
int col;
std::cin >> col;
if (col == 0){
return 0;
}
else if (col > 0){
std::string letter;
std::cin >> letter;
//std::cout << letter << std::endl;
int letter_length = letter.size();
int row = letter_length / col;
std::string message = "";
for (int i = 0; i < col; i++){
int current_row = 0;
while (current_row < row){
if ((current_row % 2)){
message += letter[current_row * col + col - i - 1];
//std::cout << "odd " << current_row * col + col - i - 1 << std::endl;
}
else {
message += letter[i + current_row * col];
//std::cout << "even: " << i + current_row * col << std::endl;
}
current_row++;
//std::cout<<"current:" << message<<std::endl;
}
}
std::cout << message <<std::endl;
}
}
}
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