> #include<iostream>
> #include<string>
> using namespace std;
> int main()
> {
> 	
> 	int n,k,w;
> 	int i,j;
> 	char p;
> 	int c=0;
> 	while(cin>>n&&n!=0)
> 	{   string x;
> 		cin>>x;
> 		k=x.size()/n;
> 	
> 		for(i=1;i<=k;i++)
> 		{
> 		 if(i%2==0)
> 		 {for(j=c,w=c+n-1;j<w;j++,w--)
> 			{        p=x[j];
> 		             x[j]=x[w];
> 					 x[w]=p;
> 			}
> 		 }
> 		 c+=n;
> 		}
>      for(j=0;j<n;j++)
> 		for(i=j;i<x.size();i+=n)
> 			cout<<x[i];
> 		
> 	}
> 	return 0;
> }