A right circular cone has a base with radius 600 and height $$200\sqrt{7}.$$ A fly starts at a point on the surface of the cone whose distance from the vertex of the cone is 125, and crawls along the surface of the cone to a point on the exact opposite side of the cone whose distance from the vertex is $$375\sqrt{2}.$$ Find the least distance that the fly could have crawled.

(第二十二届AIME2 2004 第11题)