public final Hashtable<Integer,Integer> distributionOff() {
		final Hashtable<Integer,Integer> offd = new Hashtable<Integer,Integer>();
		for (int m=0; m<this.m; m++) {
			final Integer key = off[m].size();
			Integer value = offd.get(key);
			if (value==null) offd.put(key, value);
			else value++;
		}
		return offd;
	}