Speed up Go program just a tiny bit

I wanted to refactor the file input process, but turns out someone had beaten me to it.

While doing that I noticed that removing the negation inside the `if` statement brought ~5% savings on my laptop.

Before the change:
    8981 LANGUAGE Go 1304
    8981 LANGUAGE Go 1332
    8981 LANGUAGE Go 1301
    8981 LANGUAGE Go 1314
    8981 LANGUAGE Go 1331
    8981 LANGUAGE Go 1347

After the change:

      8981 LANGUAGE Go 1266
      8981 LANGUAGE Go 1280
      8981 LANGUAGE Go 1267
      8981 LANGUAGE Go 1253
      8981 LANGUAGE Go 1290
      8981 LANGUAGE Go 1263
      8981 LANGUAGE Go 1288
      8981 LANGUAGE Go 1253