Automatic input/prt detection does not work in very special case

Consider the following response string:

```
Seed: 841433746; ans1: [1,2,3]; [1,2,3] [valid]; ans_survey: "" [score]; prt1: !; prt2: !; prt2_ersatz: !; prt3: !
```

In this case, the tool identifies `ans1` as a prt but not as an input.