In step 154, it is checked to determine whether or not a command to change {HEAD ~ the display size} or {TAIL ~ position} has already been inputted 
In step 154 , it is checked to determine whether or not a command to change { HEAD ~ the display size } or { TAIL ~ position } has already been inputted
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH