// {{{
#include <cstdio>
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <set>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <cassert>
#define SIZE(x) ((int) (x).size())
#define REP(i, n) for (int i = 0; i < (int) (n); ++i)
#define FOR(i, a, b) for (int i = (int) (a); i <= (int) (b); ++i)
#define FORD(i, a, b) for (int i = (int) (a); i >= (int) (b); --i)
#define FORE(i, c) for (__typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define DEBUG(x) { cerr << #x << ": " << (x) << endl; }
using namespace std;

typedef long long LL;
// }}}

int N;
char ch;
char text1[10047];
char text2[10047];

int main() {
	while(1){
		scanf("%d ",&N);
		if (N==0) break;
		int P = 0;
		while(scanf("%c",&ch) && ch!='\n'){
			if (ch==' ') continue;
			if (ch>='a' && ch<='z') ch = ch-'a'+'A';
			text1[P] = ch;
			P++;
		}
		text1[P]=0;
		int q = 0, f = 0;
		REP(i,N){
			f = 0;
			while(i+f*N<P) {
				text2[i+f*N] = text1[q];
				f++;
				q++;
			}
			
		}
		text2[P]=0;
		printf("%s\n",text2);
	}
}