A total of 52 students participated in the garden tour activities, including 12 people who visited the Botanical Museum, 26 people who visited the Zoological Museum, 2 people who visited the Science and Technology Museum, and 5 people who visited both the Botanical Museum and the Zoological Museum. If there are 2 people who visit the Museum and the Science and Technology Museum, 4 people who visit both the Animal Museum and the Science and Technology Museum, and 1 person who visits all three museums, how many people did not visit these three museums?
一共有52个学生参加游园活动，其中参观植物馆的有12人，参观动物馆的有26人，参观科技馆的有2人，既参观植物馆又参观动物馆的有5人，既参观植物馆又参观科技馆的有2人，既参观动物馆又参观科技馆的有4人，三个馆都参观的有1人，则有多少人这三个馆都没有参观．
<gadget id="calculator">23 - 5 - 2 - 4</gadget>
<output>12</output>

<gadget id="calculator">12 + 26 + 12 + 1</gadget>
<output>51</output>

<gadget id="calculator">52 - 51</gadget>
<output>1</output>

<result>1</result>