In addition to the first grade, a total of 120 people from the other four grades participated in the tree planting activity on the Arbor Day, including 53 people from the second and third grades, 66 people from the third and fourth grades, and 63 people from the second and fourth grades. How many people in the fifth grade participated in the tree planting activity?
植树节某校除一年级外，其他四个年级共有120人参加了植树活动，其中二、三年级共有53人参加，三、四年级共有66人参加，二、四年级共有63人参加，问五年级有多少人参加植树活动？
<gadget id="calculator">53 + 66 + 63</gadget>
<output>182</output>

<gadget id="calculator">182 / 2</gadget>
<output>91</output>

<gadget id="calculator">120 - 91</gadget>
<output>29</output>

<result>29</result>