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

void Encrypt(char * str, int step){
	int offset = 0;
	char newStr [10000];

	int len = strlen(str);
	int pos = 0;
	if (len <= step){
		puts(str);			
		return;
	}

	for(int i=0;i<len;i++){
		newStr[pos] = str[i];
		pos += step;		
		if (pos >= len){
			offset ++;
			pos = offset;
		}

	}
	newStr[len] = '\0';
	puts(newStr);			
//	printf("%s\n",newStr);
}

int main(){
	int number;
	char text [10000];
	char temp;
	int i;

	
	while(1){
		for ( i=0; i< 10000; i++)
			text[i] = '\0';

		scanf("%d",&number);
		if (number == 0)
			break;

		i=0;
	getc(stdin);
		while(1){
			scanf("%c",&temp);
			if (temp == '\n') break;
			if (temp != ' ')
				text[i++] = toupper(temp);
		}
	
		Encrypt(text, number);
	
	
	}

	return 0;
}