import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.GZIPInputStream;
public class Main {
public static void main(String[] args) throws Exception {
FileInputStream fin = new FileInputStream("a.gz");
GZIPInputStream gzin = new GZIPInputStream(fin);
FileOutputStream fout = new FileOutputStream("a.dat");
for (int c = gzin.read(); c != -1; c = gzin.read()) {
fout.write(c);
}
fout.close();
}
}