n this problem you will model a simple block world under certain rules and constraints. Rather than determine how to achieve a specified state, you will ``program a robotic arm to respond to a limited set of commands.



The Problem



The problem is to parse a series of commands that instruct a robot arm in how to manipulate blocks that lie on a flat table. Initially there are n blocks on the table (numbered from 0 to n-1) with block bi adjacent to block bi+1 for a-n this problem you will model a simple block world under certain rules and constraints. Rather than determine how to achieve a specified state, you will ``program　 a robotic arm to respond to a limited set of commands.



The Problem



The problem is to parse a series of commands that instruct a robot arm in how to manipulate blocks that lie on a flat table. Initially there are n blocks on the table (numbered from 0 to n-1) with block bi adjacent to block bi+1 for all