Are you an 'S'? If you're in South Korea, that means you've got the ideal body type. The letters (there are more of them), are descriptors of body types. Celebrities discuss them openly and regularly, advertising caters to those who conform to a certain letter, and even men and children can't escape from this.

Slate's Katy Waldman has a breakdown of this system:
South Korea has been swept up in "alphabetization," or the grouping of (mostly female) bodies into shapes based on letters from the Roman alphabet. There is the S-line—"ample breasts and buttocks when viewed from the side"—and the X-line—"long legs and arms connected by a narrow waist." The face of a woman with slim cheeks and a pointed chin follows the V-line. Cleavage is described using a W-, Y-, or V-line.
If you are a man, and you have a six pack, that means you have a good M-line. There are so many lines. S lines. V lines. W lines. Which one do you want?