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()=
  var
    n = scan()
    a = newseqwith(n,scan())
    res = -int.high.div(4)
  proc dfs(idx:int,val:int)=
    if idx==n:
      res.max=val
    else:
      var
        tmax = -int.high.div(4)
        tmin=int.high.div(4)
      tmax.max=val*a[idx]
      tmin.min=val*a[idx]
      tmax.max=val+a[idx]
      tmin.min=val+a[idx]
      tmax.max=val-a[idx]
      tmin.min=val-a[idx]
      if a[idx]!=0:
        tmax.max=val div a[idx]
        tmin.min=val div a[idx]
      dfs(idx+1,tmax)
      dfs(idx+1,tmin)
  dfs(1,a[0])
  echo res

  
solve()