赞不____ ____ 勇____直____ 相____相____
竭尽____ ____ 兴高____ ____ 直言____ ____
若数列an满足规律:a1>a2<a3>...<a2n-1>a2n<...,则称数列an为余弦数列,现将1,2,3,4,5排列成一个余弦数列的排法种数为( )