perl -we '@a=map{[split//]}<>;$x=0;$x++until$a[0][$x]eq"X";$y=0;my@r;my@q;while($y<$#a){exit(1)if($y<0);$y++;if("#"eq$a[$y][$x+1]){if("#"eq$a[$y][$x-1]){$a[$y-1][$x]="#";$y-=2;$x=pop@q;pop@r}else{push@r,"l";push@q,$x--}}else{push@r,"r";push@q,$x++}}print@r'