the middle red line is where you're standing at first. Then you go up 3 rungs (the blue lines) and then you go down 5 rungs (look at the yellow arrow and lines) And then you go up 10 rungs (follow the teal arrow up and look at the rungs) count the number of lines above the middle red line and you'll get 8. make sure that there's 8 below the middle red line because the red line has to be in the middle. now count all the lines and you'll get 17.
17
