池塘里有n片荷叶（1≤n≤1000），它们正好形成一个凸多边形。按照顺时针方向将这n片荷叶顺次编号为1，2，…，n。

有一只小青蛙站在1号荷叶上，它想跳过每片荷叶一次且仅一次（它可以从所站的荷叶跳到任意一片荷叶上）。同时，它又希望跳过的总距离最短-Pond, the n tablets lotus leaf (1 ≤ n ≤ 1000), they just form a convex polygon. These n piece lotus leaf sequential number according to the clockwise direction as 1,2, ..., n.

A little frog standing on a lotus leaf on the 1st, it would like to skip every piece of lotus leaf once and only once (it can jump from the station of the lotus leaf to any one on a lotus leaf). At the same time, it would like to skip the shortest total distance