import times, strutils, sequtils, math, algorithm, tables, sets, lists, intsets
import critbits, future, strformat, deques
template `max=`(x,y) = x = max(x,y)
template `min=`(x,y) = x = min(x,y)
template `mod=`(x,y) = x = x mod y
template scan2 = (scan(), scan())
template scan3 = (scan(), scan())
let read* = iterator: string {.closure.} =
    while true: (for s in stdin.readLine.split: yield s)
proc scan(): int = read().parseInt
proc scanf(): float = read().parseFloat
proc toInt(c:char): int =
    return int(c) - int('0')



proc solve():string=
  var
    n = scan()
    ws = newseqwith(n,scan())
    wsum = ws.sum()
    dp = newseqwith(n+1,newseqwith((n+1)*100,false))
  dp[0][0] = true

  for i in 1..n:
    for w in 0..n*100:
      if w-ws[i-1]>=0:
        dp[i][w] = dp[i-1][w] or dp[i-1][w-ws[i-1]]
      else:
        dp[i][w] = dp[i-1][w]
  if dp[n][wsum.div(2)] and wsum.mod(2)==0:
    return "possible"
  else:
    return "impossible"
  
 
  
echo solve()