package main

import "fmt"

func main() {
	var N int
	fmt.Scan(&N)
	W := make([]int, N)
	sum := 0
	for i := 0; i < N; i++ {
		fmt.Scan(&W[i])
		sum += W[i]
	}
	if sum%2 != 0 {
		fmt.Println("impossible")
		return
	}
	dp := make([]bool, sum+1)
	dp[0] = true
	for _, w := range W {
		for x := sum; x >= w; x-- {
			dp[x] = dp[x] || dp[x-w]
		}
	}
	if dp[sum/2] {
		fmt.Println("possible")
	} else {
		fmt.Println("impossible")
	}

}