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

using namespace std;

char in[10047];
char out[10047];
//string out;

int finsky[10047];

void inc(int p);

void init() {

	for ( int i = 0; i < 10007; ++i )
		finsky[i] = 0;

	for ( int i = 1; i < 10007; ++i )
		inc(i);

}

#define lastone(a) (a&(a^(a-1)))

void dec(int p) {

	for ( int i = p; i < 10007; i += lastone(i) )
		--finsky[i];

}

void inc(int p) {

	for ( int i = p; i < 10007; i += lastone(i) )
		++finsky[i];

}


int get(int n) {

	int sum = 0;

	for ( int i = n; i > 0; i -= lastone(i) )
		sum += finsky[i];

	return sum;

}

/*int find(int n, int start = 16384) {

	int sum = 0;

	for ( int i = start; i > 0; i -= lastone(i) ) {

		sum += finsky[i];

		if ( sum == n )
			return i;

		if ( sum > n ) {

			sum -= finsky[i];

			return find(n-sum+1, i);

		}

	}

	return -1;

}*/

int find(int n) {

	int start = 1;
	int end = 10007;

	while ( end - start > 2 ) {

		int mid = ( end + start ) / 2;

		int g = get(mid);

		if ( g > n )
			end = mid;
		else if ( g < n )
			start = mid;
//		else
//			return mid;

		else {

			while ( get(mid-1) == get(mid) )
				--mid;

			return mid;

		}

	}

	int i;
	for ( i = end; i >= start; --i )
		if ( get(i) == n )
			break;

	if ( n != get(i) )
		return -1;

	while ( get(i-1) == get(i) )
		--i;

	return i;

/*	if ( get(start) == n )
		return start;

	if ( get(start+1) == n )
		return start+1;

	if ( get(start+2) == n )
		return start+2;

	if ( get(start+3) == n )
		return start+3;

	return -1;*/

}

int main() {

	init();
/*	for ( int i = 1; i < 10; ++i )
		printf("%d %d\n", finsky[i], get(i));

	for ( int i = 1; i < 10; ++i )
		printf("%d\n", find(i));

//	dec(1);
//	dec(2);
	dec(3);
	dec(7);

	for ( int i = 1; i < 10; ++i )
		printf("%d %d\n", finsky[i], get(i));

	return 0;*/

	int n;

	while ( 1 ) {

		scanf("%d", &n);

		if ( ! n )
			return 0;

		int c;
		int p = 0;

		getchar();

		while ( ( c = getchar() ) ) {

			if ( c == '\n' )
				break;

			if ( c < 33 )
				continue;

			c = toupper(c);

			in[p++] = c;

		}

		in[p] = 0;

//		printf("%s\n", in);

		int sum = 0;

		while ( sum < p ) {

			for ( int i = 0; i < p-sum; i += n-1 ) {

				int poz = find(i+1);
				dec(poz);
				
				--poz;

				out[poz] = in[sum];
//				printf("%d %d %d %c\n", poz, sum, i, in[sum]);

				++sum;


			}


		}

		out[p] = 0;
		printf("%s\n", out);


	}

	return 0;

}