class ReadCode{
    public static void main (String[] args){
        int[]listA={8,7,6,5};
        int[]listB={4,3,2,1};
        int max=listA.length;
        if(listA.length>listB.length){
            max=listB.length-1;
        }
	recurse(listA, listB, max);

	for(int i=0; i<listA.length; i++){
		System.out.print(listA[i]+".");
		System.out.print(listB[i]+".");
	}
}

static void recurse(int[] list1, int[] list2, int elem){
	if(elem<=0){
		return;
	}
	else{
		recurse(list1, list2, elem-1);
		list2[0]=list2[list2.length-1];
		list2[list2.length-1]=list1[0];
		list1[0]+= elem;
		}
	}
}