H
hotgirl_98


=((Chung minh rang voi moi n # 0 thi (3n-1) va(4n-1) nguyen to cung nhau=((
giup e voi nha cac Hotboy 
E dang can gap giup e nha!!! Boy nao lam duoc thi E xin cam on

E dang can gap giup e nha!!! Boy nao lam duoc thi E xin cam on