A rectangular floor tile is 40 cm long and 26 cm wide. If a square floor is paved with this kind of bricks, what is the shortest side length of the paved square floor?
一块长方形地面砖长为40厘米，宽为26厘米．用这种砖铺一块正方形地面，铺成的正方形地面的边长最短多少．
<gadget id="calculator">2 * 2 * 2 * 5 * 13</gadget>
<output>520</output>

<result>520</result>