If have a custom made telescope with these specifications then what’s the focal length of my telescope? (refractor telescope only

If have a custom made telescope with these specifications then what’s the focal length of my telescope? (refractor telescope only )
_Specifications:_*Objective diameter*: 90mm*Distance between lenses*: 230mm*Eyepiece focal length*: 4mm*Eyepiece size*: 31.7mm respond fast. Also give a simplified answer for a answer tag. Thanks!​