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


int main(){
	
	char str[10001];
	char str2[10001];
	int sifra, delka, i;
	char c, k;
	while(1){
		scanf("%d", &sifra);
		if(sifra == 0){
			return 0;
		}

		i = 0;
		while((c = getchar()) != '\n'){
		}
		while(1){
			scanf("%c", &c);
			if(c == '\n'){
				break;		
			}
			if(c == ' '){
				continue;
			}
			str[i] = c;
			i++;
		}
		str[i] = '\0';
		delka = i;
		k = 0;
		for(int j = 0; j < delka; j++){
			str2[(j * sifra) % delka] = toupper(str[j]);
		}		
		str2[delka] = '\0';
		printf("%s\n", str2);
	}
	return 0;
}