The school summer camp team plans to plant colorful flags on one side of the 90-meter-long playground, with a red flag every 3 meters and a yellow flag every 5 meters, but the two colors of flags are not placed in the same place at the same time, (that is, there are Where there is a red flag, there is no yellow flag, and where there is a yellow flag, there is no red flag) and both ends must be inserted. How many colored flags can be placed on the side of the playground?
学校夏令营小组准备在90米长的操场一边插上彩旗，每隔3米插一面红色旗帜，每隔5米插上一面黄色旗帜，但两种颜色的旗帜不同时插一个地方，(也就是有了红旗的地方就不插黄旗，有了黄旗的地方就不插红旗)并且两端都要插，操场边上一共可以插多少面彩旗？
<gadget id="calculator">90 / 3</gadget>
<output>30</output>

<gadget id="calculator">30 + 1</gadget>
<output>31</output>

<gadget id="calculator">90 / 5</gadget>
<output>18</output>

<gadget id="calculator">18 + 1</gadget>
<output>19</output>

<gadget id="calculator">31 + 19</gadget>
<output>50</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">90 / 15</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<gadget id="calculator">50 - 7</gadget>
<output>43</output>

<result>43</result>