A box of mass 20 𝑘𝑔 is pulled at constant speed across a floor by a rope. The rope makes an angle of 45° with the horizontal. Assuming that friction is negligible, the work done in pulling the box by a distance of 20 𝑚 is _____ 𝐽 (rounded off to the nearest integer). (Use $𝑔 = 9.8 𝑚𝑠^{−2}$)