Formalize a streamlined version of the sheep bank protocol, described in the lecture, as an MLS model, including the clay token and (optional) trading with Charlie. Use the following sets: LSOA={L1,L2},L2>L1.={Alice,Bobscharlie},={Sheep,Token},={Read,WriteL1,WriteL2,ChTlvl1,ChTlvl2} Include the following steps(each requiring one or more states): Step 1. Alice has her sheep Step 2. Alice deposits sheep at Charlie's bank, gets token Step 3. Alice trades token to Charlie Step 4. Alice or Charlie get sheep back from Charlie for token. Alice and Charlie only have clearance for level L1. Bob should be at level L2 at the beginning and at the end of the process