import java.util.*; import java.util.zip.*; import java.util.List; import java.util.regex.*; import java.util.concurrent.*; import java.util.concurrent.atomic.*; import java.util.concurrent.locks.*; import javax.swing.*; import javax.swing.event.*; import javax.swing.text.*; import javax.swing.table.*; import java.io.*; import java.net.*; import java.lang.reflect.*; import java.lang.ref.*; import java.lang.management.*; import java.security.*; import java.security.spec.*; import java.awt.*; import java.awt.event.*; import java.awt.image.*; import javax.imageio.*; import java.math.*; class main { static boolean setBit_trueIfChanged(BitSet b, int bit) { return setBit_trueIfChanged(b, bit, true); } static boolean setBit_trueIfChanged(BitSet b, int bit, boolean value) { if (b == null || b.get(bit) == value) return false; b.set(bit, value); return true; }}