Well 6 k, if you include the warm up and warm down walks.
I have to admit to wanting to stop after practically every 5 minute prompt on the app, but at 35mins 4.2k seemed too tantilisingly close to finish! The last .3k was spent running in circles round the car park my phone clutched desperately aloft, willing the numbers to tick over...and the second they did, i collapsed in a heap on the bonnet of my car. (dutifully completed the 5 min warm down walk before driving away though!)
Anway, seems i need to do something about my pace and see if i can reduce that 43 minutes!