Input:
------

40 23
########################################
#~      ~ ~~  ~  ~ ~~   ~ ~~    ~ ~ ~~ #
#~~ ~          ~~   ~   ~ ~~         ~ #
#~# ~~   ~~~~      ~  ~~~~  ~    ~~~  ~#
# ~        ~   ~ ~~ #~~       ~        #
#~~  ~~~   ~ ~ ~      ~ ~~ ~  ~  ~  ~  #
#     ~~  ~  ~ ~ ~~~       H    ~  #~  #
#  O~  ~  #  ~~~ ~      ~ ~~  ~  ~ ~~  #
#       ~ ~H~~   ~~ ~ #        ~~   ~  #
# ~~         ~ ~~~  ~~   ~~~~      ~  ~#
#~  ~    ~~~  ~   ~        ~   ~ ~~  ~~#
#     ~      # ~ ~~  ~~~   ~ ~ ~ #    ~#
#~ ~ ~~  ~  ~   H     ~~  ~~ ~ ~ ~~~   #
#       ~   ~   ~   ~  ~     ~~~ ~     #
# ~~  ~  ~ ~~   ~       ~ ~ ~     ~    #
#      ~~   ~   ~  ~         ~      ~~ #
#~ ~     #    ~~~~  ~    ~~~H   # ~    #
#  ~   ~ ~   ~        ~          ~~  ~ #
#  ~   ~     #~  ~   ~~  ~  ~         ~#
# ~~ ~ ~  ~~                ~   ~      #
#    ~~~        ~ ~~  ~  ~  ~   ~      #
# ~ ~     ~            ~~   ~   ~  ~   #
########################################
RRUURRRRRURDDDDDDDDDRRDDLLLLLLUUUUUULLLUUUURRRDDDDDDDDLLLUUUUUURUURRDDDDDDD

Output:
-------
0

Result after the 75th (the last) move:

########################################
#~      ~ ~~  ~  ~ ~~   ~ ~~    ~ ~ ~~ #
#~~ ~          ~~   ~   ~ ~~         ~ #
#~# ~~   ~~~~      ~  ~~~~  ~    ~~~  ~#
# ~  ~      ~  ~ ~~ #~~       ~        #
#~~         ~~~~      ~ ~~ ~  ~  ~  ~  #
#   ~ ~   ~  ~ ~ ~~~            ~  #~  #
#     ~   #  ~~~ ~      ~ ~~  ~  ~ ~~  #
#       ~ ~ ~~   ~~ ~ #        ~~   ~  #
# ~~   H     ~ ~~~  ~~   ~~~~      ~  ~#
#~    H H~~   ~   ~        ~   ~ ~~  ~~#
#     ~H     # ~ ~~  ~~~   ~ ~ ~ #    ~#
#~ ~ ~~O ~  ~         ~~  ~~ ~ ~ ~~~   #
#       ~     ~ ~   ~  ~     ~~~ ~     #
# ~~  ~~ ~ ~~   ~       ~ ~ ~     ~    #
#  ~~~~~        ~  ~         ~      ~~ #
#~ ~     # ~  ~~~~  ~    ~~~    # ~    #
#  ~   ~ ~   ~        ~          ~~  ~ #
#  ~   ~     #~  ~   ~~  ~  ~         ~#
# ~~ ~ ~  ~~                ~   ~      #
#    ~~~        ~ ~~  ~  ~  ~   ~      #
# ~ ~     ~            ~~   ~   ~  ~   #
########################################