#include<cstdio>

#include<cstring>

#include<cstdlib>

#include<cctype>

#include<cmath>

#include<iostream>

#include<sstream>

#include<iterator>

#include<algorithm>

#include<string>

#include<vector>

#include<set>

#include<map>

#include<stack>

#include<deque>

#include<queue>

#include<list>

#define lowbit(x) (x & (-x))

const double eps = 1e-8;

inline int dcmp(double a, double b){

    if(fabs(a - b) < eps) return 0;

    return a > b ? 1 : -1;

}

typedef long long LL;

typedef unsigned long long ULL;

const int INT_INF = 0x3f3f3f3f;

const int INT_M_INF = 0x7f7f7f7f;

const LL LL_INF = 0x3f3f3f3f3f3f3f3f;

const LL LL_M_INF = 0x7f7f7f7f7f7f7f7f;

const int dr[] = {0, 0, -1, 1, -1, -1, 1, 1};

const int dc[] = {-1, 1, 0, 0, -1, 1, -1, 1};

const int MOD = 1e9 + 7;

const double pi = acos(-1.0);

const int MAXN = 200 + 10;

const int MAXT = 10000 + 10;

using namespace std;

char s[MAXN];

char pic[MAXN][MAXN];

int main(){

    int c;

    while(scanf("%d", &c) == 1){

        if(!c) return 0;

        memset(pic, ' ', sizeof pic);

        scanf("%s", s);

        int len = strlen(s);

        int r = 0;

        for(int i = 0; i < len; ++i){

            if(i % c == 0) ++r;

            if(r & 1){

                pic[r][i - (r - 1) * c] = s[i];

            }

            else{

                pic[r][c - (i - (r - 1) * c) - 1] = s[i];

            }

        }

        for(int i = 0; i < c; ++i){

            for(int j = 1; j <= r; ++j){

                printf("%c", pic[j][i]);

            }

        }

        printf("\n");

    }

    return 0;

}