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

int main(void){
	char ret[10010];
	char pom[10010];
	char vysl[10010];
	char c;
	int n;
	while (1 == 1){
		scanf("%d", &n);
		if (n == 0) return 0;

		
		int j = 0;
		while ((c = getchar()) != '\n')
		{
			ret[j] = c;
			j++;
		}
		ret[j] = 0;
		j = 0;
		for (int i = 0; i<strlen(ret); i++){
			if (ret[i] == ' ') continue;
			if (ret[i] >= 'a') ret[i] = ret[i] - ('a' - 'A');
			pom[j] = ret[i];
			j++;
		}
		pom[j] = 0;
		if (strlen(pom) > 1)
		{
			int zaciatok = 0;
			int ulozenie = 0;
			int final = 0;
			//printf("%s\n", pom);
			memset(vysl, 0, sizeof(vysl));
			//int posun = 0;
			//if (j%2 == 0) posun = 1; 
			j--;
			while (final < j){
				ulozenie = zaciatok;
				while (ulozenie < j){
					//printf("zac %d  uloz %d  fin%d \n",zaciatok,ulozenie,final);
					//vysl[final] = pom[ulozenie];
					vysl[ulozenie] = pom[final];
					final++;
					ulozenie += n;//+posun;
					//printf("%s\n", vysl);
				}
				zaciatok++;
			}
			/*
			int pos = strlen(pom);
			for (int i = 0; i<strlen(pom); i++){
				vysl[((i*n)/pos) + ((i*n)%pos)] = pom[i];
			}
			*/
			
			
			vysl[j] = 0;
			printf("%s\n", vysl);
		}
	}
}