Thinking it trough. Even better would be ...
End index should be max(0,Touch.TouchCount - 1)
To not allow the loop to count from zero to - 1. This is only to have it even more performant. Not dooing this will not create an error.
Also, you have to decide if a 3th touch is allowed.
If not, you need to add a system > compare 2 values > Touch.TouchCount <= 2.
Touch.TouchCount is the expression that returns the amount of touches on the screen.