#include <stdlib.h>
#include <iostream>
#include <string>
using namespace std;
#define N 100
char a[100][100];
int main()
{
int n;
string s;
int h;
while(cin>>n&&n!=0)
{
cin>>s;
int size=s.length();
h=size/n;
for(int i=0;i<h;i++)
{
if(i%2==0)
{
for(int j=0;j<n;j++)
{
a[i][j]=s[i*n+j];
//cout<<a[i][j]<<"***";
}
//cout<<endl;
}
else
{
for(int j=0;j<n;j++)
{
a[i][j]=s[(i+1)*n-j-1];
//cout<<a[i][j]<<"---";
}
//cout<<endl;
}
}
for(int i=0;i<n;i++)
{
for(int j=0;j<h;j++)
{
cout<<a[j][i];
}
}
cout<<endl;
}
//system("pause");
return 0;
}