func main() var n: int var ww: []int var wtotal : int var existed: bool var ww_str: [][]char do n :: cui@input().toInt(&existed) do ww_str :: cui@input().split(" ") do ww :: #[n]int do wtotal :: 0 for cnt(0, n-1) do ww[cnt]:: ww_str[cnt].toInt(&existed) do wtotal :: wtotal + ww[cnt] end for var res: int do res:: math@knapsack(ww, ww, wtotal/2, false) if (res <> wtotal/2) do cui@print("impossible") else do cui@print("possible") end if end func