$/=$n=<>;$_=<>.1x$n++;eval'print/^X\.Y$/s+--$n+s/\G\S*?\K(?=X\.Y1)//sg-$n--+/^Y\.Y
1/s+s/^A*\.A*$//mg'=~s'Y'.{$n}X'gr=~s'X'(A.{$n})*'gr