I have a problem with 5 test case. Firs I had Runtime Error, when I add lines:

   if(nextWord == null)
      continue;

Runtime Error changed to WA.

I'm using Java and i read my input as follow:
    StreamTokenizer in = in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));

    private static int nextInt() throws IOException {
        in.nextToken();
        return (int) in.nval;
    }

    private static String nextString() throws IOException {
        in.nextToken();
        return in.sval;
    }