From a rectangular piece of paper 2109 mm long and 627 mm wide, cut a square with as large a side as possible, and if the rest is not a square, cut another piece with as large a side as possible from the remaining piece of paper According to the above process, keep repeating, what is the side length of the final cut square in millimeters?
从一张长2109毫米，宽627毫米的长方形纸片上，剪下一个边长尽可能大的正方形，如果剩下的部分不是正方形，那么在剩下的纸片上再剪下一个边长尽可能大的正方形，按照上面的过程，不断地重复，最后剪得的正方形的边长是多少毫米．
<result>57</result>