The floor of the school cafeteria was newly paved with floor tiles, one of which was black. Zhang Hao counted and found that the position of this black floor tile was the 18th from left to right, and the 23rd from right to left. Counting from front to back is the 29th block, and counting from back to front is the 22nd block. Please do the math, how many floor tiles are laid in the restaurant?
学校餐厅的地面新铺了地砖，其中有一块是黑色的，张浩数了一下，发现这块黑色地砖的位置从左往右数是第18块，从右往左数是第23块，从前往后数是第29块，从后往前数是第22块．请你算一算，餐厅里一共铺了多少块地砖？
<gadget id="calculator">23 - 1</gadget>
<output>22</output>

<gadget id="calculator">18 + 22</gadget>
<output>40</output>

<gadget id="calculator">22 - 1</gadget>
<output>21</output>

<gadget id="calculator">29 + 21</gadget>
<output>50</output>

<gadget id="calculator">40 * 50</gadget>
<output>2_000</output>

<result>2_000</result>