According to the pattern shown below, how many triangles (s) is/are there from 1st to 449th symbol counting from the right?

According to the pattern shown below, how many triangles (s) is/are there from 1st to 449th symbol counting from the right?


Pattern: Quy luật; Triangle: Hình tam giác; Symbol: Kí hiệu; Right: Bên phải.
 
----- Nội dung dịch tự động từ ảnh -----
.. A O O 4 O ^ o O 4 O - 0 0 4 O a O O