#include <cstdio>
#include <cstdlib>
#include <cctype>

int main(int argc, char* argv[]){
	while(1){
		int krok = 0;
		char dummy;
		scanf("%d%c", &krok, &dummy);		
		if(krok == 0) break;
		char buffer[10000];
		int delkavstupu=0;
		while(1){
			buffer[delkavstupu] = getc(stdin);
			if(buffer[delkavstupu] == '\n') break;
			if(buffer[delkavstupu] == ' ') continue;
			buffer[delkavstupu] = (char)toupper(buffer[delkavstupu]);
			delkavstupu++;
		}
		char* vystup=(char*)malloc(delkavstupu * sizeof(char));
		int counter = 0;
		for(int i = 0; i < krok; i++){
			for(int j = i; j < delkavstupu; j+=krok){
				vystup[j] = buffer[counter++]; 
			}
		}

		for(int i = 0; i < delkavstupu; i++){
			printf("%c", vystup[i]);
		}
		printf("\n");
		free(vystup);
	}
	return 0;
}