Well, the pilots themselves would say 178 flares, or 154 chaff + 24 flares. MFCD and EMFCD add their own variety of flares and chaff, but I want to draw attention to what MFCD is,
“Modular Flare and Chaff Dispenser”
The F-35 pilots book already refers to the undertail dispensers as “flare catridges” in one image, while specifically calling out the chaff catridges on the EMFCD pods on the same page. The cassettes containing these flares are described as visually identical, and the fact the whole program was called MODULAR heavily implies they were interchangable by design, but standard operation was usually all chaff where available, as the aircraft was meant to do low flying strikes on enemy locations, vehicles and even radar (if you were brave enough) by doctrine. Therefore there was rarely a reason to supply all flares, but the modularity of it allowed them to be swapped. The only exceptions for this, were the right wing root flares (12) and the six on each side of the exhaust (12). Those were only flares as they could not be changed (and in the ultimate irony, those are the only ones Gaijin allowed us to change)
