cms.EDProducer("TrackingParticleNumberOfLayersProducer",\ 
    mightGet = cms.optional.untracked.vstring,\ 
    simHits = cms.VInputTag("g4SimHits:TrackerHitsPixelBarrelLowTof", "g4SimHits:TrackerHitsPixelEndcapLowTof"),\ 
    trackingParticles = cms.InputTag("mix","MergedTrackTruth")\ 
)\