diff --git a/src/main/java/org/ids_mannheim/TotalNGram.java b/src/main/java/org/ids_mannheim/TotalNGram.java
index ceec820..82a8f56 100644
--- a/src/main/java/org/ids_mannheim/TotalNGram.java
+++ b/src/main/java/org/ids_mannheim/TotalNGram.java
@@ -8,6 +8,7 @@
 import java.io.FileOutputStream;
 import java.io.PrintStream;
 import java.util.ArrayList;
+import java.util.List;
 import java.util.Locale;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -35,7 +36,7 @@
     }
 
     @CommandLine.Parameters(arity = "1..*", description = "input files")
-    private final ArrayList<String> inputFiles = new ArrayList<>();
+    private ArrayList<String> inputFiles = new ArrayList<>();
     @CommandLine.Option(names = {"-L",
             "--log-file"}, defaultValue = DEFAULT_LOGFILE, description = "log file name (default: ${DEFAULT-VALUE})")
     String logFileName;
@@ -122,7 +123,19 @@
         }
 
         ConcurrentHashMap<String, AtomicInteger> map = new ConcurrentHashMap<>();
-        long totalFilesSizes = inputFiles.parallelStream().mapToLong(fname -> new File(fname).length()).sum();
+
+        long totalFilesSizes = inputFiles.parallelStream().mapToLong(fname -> {
+            long l = new File(fname).length();
+            if (l == 0) {
+                logger.severe("File "+fname+" does not exist or is empty.");
+                System.exit(-1);
+            }
+            return l;
+        }).sum();
+        inputFiles = (ArrayList<String>) inputFiles.parallelStream().sorted((a, b) ->
+           Long.compareUnsigned(new File(b).length(), new File(a).length())
+        ).collect(Collectors.toList());
+
         etaPrinter = new Progressbar(totalFilesSizes);
         BlockingQueue<Integer> queue = new LinkedBlockingQueue<>(inputFiles.size());
         ExecutorService es = Executors.newCachedThreadPool();