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 i := 0; i < N; i++ {
		for j := 0; j < sum; j++ {
			if !dp[j] || j+W[i] > sum {
				continue
			}
			dp[j+W[i]] = true
		}
	}
	res := "impossible"
	if dp[sum/2] {
		res = "possible"
	}
	fmt.Println(res)
}