[[1,2,3],[4,5]]
[[1],[2,3,4],[5]]
[[1,2,3,4,5]]
[[1,2,3,4,5]]
[[1],[2],[3],[4],[5]]
[[1],[2],[3],[4],[5]]
[[1,2],[3,4],[5]]
[[1],[2,3],[4,5]]
[]
[]
[]
[]
[]
[]
[[1]]
[[1]]
[[2]]
[[2]]