Hi to everyone!

Traying to resolve Perfect Numbers problems

I checked the code and works for tests but execution time is around 23 second for large numbers tests and finally finish with time out message. Any idea to solve this problem without using between predicate?

```
classify(Number, perfect):- factors(Number, Number, [_|R]), sum_list(R, Number).
classify(Number, abundant):- factors(Number, Number, [_|R]), sum_list(R, R2), Number < R2.
classify(Number, deficient):- factors(Number, Number, [_|R]), sum_list(R, R2), Number > R2.
factors(_, 1, [1]).
factors(N, Range, [Range|R]):- Range > 1, Range2 is Range - 1, 0 is mod(N, Range), factors(N, Range2, R).
factors(N, Range, R):- Range > 1, Range2 is Range - 1, Mod is mod(N, Range), Mod \= 0, factors(N, Range2, R).
```

Thank you so much and have a lovely day!