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

#define MAX 10000


int main(void) {

	while(1) {
		int num;
		char str[MAX+1];

		scanf("%d", &num);
		if(num == 0) return 0;

		int i = 0;
		int len = 0;
		char res[MAX+1];
		memset(res, 0, MAX+1);
		int c=getc(stdin) ;
		while((c = getc(stdin)) != '\n') {
			if(c != ' ') {
				str[i++] = toupper(c); len++;
			}			
		}		

		i = 0;
		int pom = 0;
		int pos = 0;
		for(i; i < num; i++){
			pom = i;
			while(pom < len){
				res[pom] = str[pos];
				pos++;
				pom += num;
			}		
		}

		printf("%s\n",res);		
	}
}