func main()

    var n: int
    var ww: []int
    
    var existed: bool
    var ww_str: [][]char
    
    do n :: cui@input().toInt(&existed)
    do ww_str :: cui@input().split(" ")
    
    do ww :: #[n]int
    
    for cnt(0, n-1)
        do ww[cnt]:: ww_str[cnt].toInt(&existed)
    end for
    
    var dp: []bool :: #[10001]bool
    
    do dp[0] :: true
    for i(0, n-1)
        var w : int :: ww[i]
        for c(10000, 0, -1)
            if (dp[c])
                do dp[c+w] :: true
            end if
        end for
    end for
    
    var sum: int :: 0
    for i(0, n-1)
        do sum :+ ww[i]
    end for
    
    {
    if (sum%2 = 1 | dp[sum/2] = false)
        do cui@print("impossible")
    else
        do cui@print("possible")
    end if
    }
    do cui@print(
    |   (sum%2 = 1 | dp[sum/2] = false)
    |   ?("impossible", "possible")
    | )
    
end func