eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
ddddddddddddddddddddddddddddd
uppppppppppppppppppppppppppppppppppp
eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
đánh bóng nguyên con wave khoảng bao nhiêu vậy a ?