void deleteNElement(int number, struct element *begining, struct element *end) {
	int i;
	struct element *current = begining;
	struct element *next = current->nastepny;
	struct element *prev = current->poprzedni;
	for(i = 1; i<=number; i++){
		if(i == number){
			if(next == null) end = prev;
			else next->poprzedni = current->poprzedni;
			if(prev == null) begining = next;
			else prev->nastepny = current->nastepny;
			free(current);
			return;
		}
		if(current->nastepny != null){
			current = current->nastepny;
		} else {
			return;
		}
	}
}