Gabriel drew a vertical line segment of length 4 inches and labeled the top endpoint A and the other endpoint B. Next, he drew a line segment of length 2 inches starting at A and moving to the left. Beginning at the midpoint of AB, Gabriel moved his pencil 4 units to the right and 1 unit up and marked point C. Then, he moved his pencil 2 units down and marked point D. He drew two circles of radius 1 unit centered at C and D. Finally, Gabriel erased points C and D. What number did Gabriel draw?