Arrange 1996 □ in a row, and three children A, B, and C take turns to dye these □. A dyes the first □ red, B dyes the next 2 □ yellow, C dyes the next 3 □ blue, A dyes the next 4 □ red, B dyes the next 4 □ The next 5 □ are dyed yellow, C dyes the next 6 □ blue, ... until all □ are dyed. How many □ are dyed blue?
把1996个□排成一排，甲、乙、丙三个小朋友轮流对这些□染色．甲把第一个□染成红色，乙把接下去的2个□染成黄色，丙把接下去的3个□染成蓝色，甲再把接下去的4个□染成红色，乙把接下去的5个□染成黄色，丙把接下去的6个□染成蓝色，…，直至将全部□染上色为止．其中被染成蓝色的□共有多少个．
<gadget id="calculator">3 + 60</gadget>
<output>63</output>

<gadget id="calculator">63 * 20</gadget>
<output>1_260</output>

<gadget id="calculator">1_260 / 2</gadget>
<output>630</output>

<gadget id="calculator">62 * 63</gadget>
<output>3_906</output>

<gadget id="calculator">3_906 / 2</gadget>
<output>1_953</output>

<gadget id="calculator">1_996 - 1_953</gadget>
<output>43</output>

<gadget id="calculator">630 + 43</gadget>
<output>673</output>

<result>673</result>