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 String unnullForIteration(String s) { return s == null ? "" : s; } static Collection unnullForIteration(Collection l) { return l == null ? immutableEmptyList() : l; } static List unnullForIteration(List l) { return l == null ? immutableEmptyList() : l; } static int[] unnullForIteration(int[] l) { return l == null ? emptyIntArray() : l; } static char[] unnullForIteration(char[] l) { return l == null ? emptyCharArray() : l; } static double[] unnullForIteration(double[] l) { return l == null ? emptyDoubleArray() : l; } static Map unnullForIteration(Map l) { return l == null ? immutableEmptyMap() : l; } static Iterable unnullForIteration(Iterable i) { return i == null ? immutableEmptyList() : i; } static A[] unnullForIteration(A[] a) { return a == null ? (A[]) emptyObjectArray() : a; } static BitSet unnullForIteration(BitSet b) { return b == null ? new BitSet() : b; } //ifclass Symbol static long unnullForIteration(Long l) { return l == null ? 0L : l; } static List immutableEmptyList() { return Collections.emptyList(); } static int[] emptyIntArray_a = new int[0]; static int[] emptyIntArray() { return emptyIntArray_a; } static char[] emptyCharArray = new char[0]; static char[] emptyCharArray() { return emptyCharArray; } static double[] emptyDoubleArray = new double[0]; static double[] emptyDoubleArray() { return emptyDoubleArray; } static Map immutableEmptyMap() { return Collections.emptyMap(); } static Object[] emptyObjectArray_a = new Object[0]; static Object[] emptyObjectArray() { return emptyObjectArray_a; } }