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.*; import java.time.Duration; class main { static double alphaChannelAverage(int[] pixels) { int n = pixels.length; long sum = 0; for (int i = 0; i < n; i++) sum += rgbAlpha(pixels[i]); return doubleRatio(sum, n); } static int rgbAlpha(int rgb) { return (rgb >> 24) & 0xFF; } static double doubleRatio(double x, double y) { return y == 0 ? 0 : x/y; } }