# The Turing Machine program below is designed to detect strings of A's followed by an equal number of B's
# Assumption: the machine starts in state 1 looking at the first (leftmost) character of a string
# Input: one string consisting of 0 or more A's and B's.  No blanks can occur between characters (the
#        machine won't work in this case)
# Ouput: if there is nothing on the tape, we count this as a "Yes" since it is 0 A's followed by 0 B's
#           so, the machine will write an 'Y' on the tape and halt
#        if the string on the tape contains some (non-zero) number of A's followed by the same number of B's
#           it will halt with 'Y' on the tape (and it will erase all the A's and B's in the process)
#        if the string on the tape contains something other than A's followed by an equal number of B's,
#           then the machine will halt and write 'N' on the tape (and may leave some of the
#           original string on the tape as well.
# How to Use: Open this file in a text editor and select/highlight the TM rules below and then copy/paste
#        them into the "Programming" window of the simulator.  After put the lines in there, click
#        on the "Install Program" button. If this works fine, you should see " Entering program...
#        Machine programmed successfully" in the "Message Box." If you see some kind of error message
#        in the Message Box, then you'll have to play around to see what's wrong.  The simulator seems
#        to be fairly picky about format - so you might need to check if there are extra blank spaces or
#        other symbols.  Let me know if you're having trouble. 

1,B,H,N,>
1,A,2,_,>
1,_,H,Y,>
2,A,2,A,>
2,B,3,B,>
2,_,H,N,>
3,B,3,B,>
3,A,H,N,>
3,_,4,_,<
4,B,5,_,<
5,A,5,A,<
5,B,5,B,<
5,_,1,_,>