$16$
23. In the garden, 15 roses, 9 tulips, and 19 sunflowers are in full bloom. The flower fairy waves her magic wand for the first time, turning 7 roses into tulips; the second time, she turns 11 tulips into sunflowers; the third time, she turns 13 sunflowers into roses. At this point, the number of roses in the garden is $\qquad$ more than the number of tulips.