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 java.util.function.*; 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 java.awt.geom.*; import javax.imageio.*; import java.math.*; class main { static List nullPlus(Collection l) { return itemPlusList(null, l); } static List itemPlusList(A a, Collection l) { return concatLists(ll(a), l); } static List concatLists(Iterable... lists) { List l = new ArrayList(); if (lists != null) for (Iterable list : lists) addAll(l, list); return l; } static List concatLists(Collection> lists) { List l = new ArrayList(); if (lists != null) for (Iterable list : lists) addAll(l, list); return l; } static List ll(A... a) { ArrayList l = new ArrayList(a.length); if (a != null) for (A x : a) l.add(x); return l; } static void addAll(Collection c, Iterable b) { if (c != null && b != null) for (A a : b) c.add(a); } static boolean addAll(Collection c, Collection b) { return c != null && b != null && c.addAll(b); } static boolean addAll(Collection c, B... b) { return c != null && b != null && c.addAll(Arrays.asList(b)); } static Map addAll(Map a, Map b) { if (a != null && b != null) a.putAll(b); return a; } }