Sum Only Values Positve After Sum Expression

[JASalinas]

I have a KPI From an Expression: Sum({<[Account]={"138*"}> - <[FUND]={"20*"}>}(Amount))  on a Table show me that:

But I want only the Sum of the Amount Positive or Negative after this Sum Positive: 109,395.52 or Negative (-792.78) + (-22,547.98) = -23,440.76

Thank you!. I am a beginner in Qlik Sense.

Thank you Again!.