else {
intervals = includeSortedSet.subtractRegions(excludeSortedSet);
// logging messages only printed when exclude (-XL) arguments are given
final long toPruneSize = includeSortedSet.coveredSize();
final long toExcludeSize = excludeSortedSet.coveredSize();
final long intervalSize = intervals.coveredSize();
logger.info(String.format("Initial include intervals span %d loci; exclude intervals span %d loci", toPruneSize, toExcludeSize));
logger.info(String.format("Excluding %d loci from original intervals (%.2f%% reduction)",
toPruneSize - intervalSize, (toPruneSize - intervalSize) / (0.01 * toPruneSize)));
}