package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func Scanner() string {
	sc.Scan()
	return sc.Text()
}

func main() {
	buf := make([]byte, 0)
	sc.Buffer(buf, 100000007)
	sc.Split(bufio.ScanWords)
	n, _ := strconv.Atoi(Scanner())
	w := make([]int, n)
	sum := 0
	for i := 0; i < n; i++ {
		w[i], _ = strconv.Atoi(Scanner())
		sum += w[i]
	}

	dp := make([]bool, sum+1)
	dp[0] = true
	for _, i := range w {
		for j := sum; j >= i; j-- {
			dp[j] = dp[j] || dp[j-i]
		}
	}
	ans := "impossible"
	if sum%2 == 0 && dp[sum/2] {
		ans = "possible"
	}
	fmt.Println(ans)
}