#include <cstring>
#include <cstdio>
#include <cctype>
#define MAXLEN 10002
int main(int argc, char** argv)
{
	char poleIn[MAXLEN];
	char poleOut[MAXLEN];
	while (true) {
		int key;
		scanf("%d", &key);
		if (key==0)
			break;
		getchar();
		char c;
		int pozice = 0;
		while ((c = fgetc(stdin)) != '\n') {
			if(!isspace(c)) {
				poleIn[pozice++]=toupper(c);
			}
		}
		
		poleIn[pozice]='\0';
		int delka = pozice;
		
		int i;
		int n = 0;
		int preteceni = 0;
		for (i = 0; i < delka; i++) {
			poleOut[n] = poleIn[i];
			n += key;
			if (n >= delka) {
				preteceni++;
				n = preteceni;
			}
		}
		/*int modul = 0;
		for (int i = 0; i < delka; i++) {
			if (i*key > delka) {
				modul++;
				
			}
			poleOut[i % key + modul] = poleIn[i];
		}
		*/
		poleOut[delka] = '\0';
		printf("%s\n", poleOut);
	}
	return 0;
}