#include <iostream>
#include <cctype>
#include <cstdio>
using namespace std;

int main(void){
	char input[10000],*output;
	char znak;
	int step;
	int i=0;
	while(1){
		i=0;
		fflush (stdin);
		cin>>step;
		if(step==0)break;
		getchar();		
		while((znak = getchar()) != '\n'){
			if(znak==' ')continue;
			input[i] = toupper( znak);
			i++;
		}
		input[i]='\0';
		if(step>=i){cout<<input<<endl;continue;}
		output=new char[i];
		int a = 0;
		for(int j=0;j<i;j++){
			output[a]=input[j];
			a+=step;
			a%=i;
		}
		cout<<output<<endl;
		delete [] output;
	}
	return 0;
}