import java.awt.Point;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
public class Main {
//	public static final int INF = 1 << 30;
	public static int[] dp;
	public static int n;
	public static void main(String[] args) throws NumberFormatException, IOException{
		ContestScanner in = new ContestScanner();
		n = in.nextInt();
		int max = n*100;
		dp = new int[max+1];
//		for(int i=0; i<=n; i++){
//			dp[i] = INF;
//		}
		dp[0] = 1;
		int sum = 0;
		for(int i=0; i<n; i++){
			int w = in.nextInt();
			sum += w;
			for(int j=max; j>=0; j--){
				if(dp[j] > 0 && j+w <= max) dp[j+w] = 1;
			}
		}
		if(sum%2 == 1 || dp[sum/2] == 0) System.out.println("impossible");
		else System.out.println("possible");
	}
	
	public static void dfs(int pos, int turn){
		int bit = Integer.bitCount(pos);
		int nxt = pos + bit;
		if(0 < nxt && nxt <= n){
			if(dp[nxt] > turn+1){
				dp[nxt] = turn+1;
				dfs(nxt, turn+1);
			}
		}
		nxt = pos - bit;
		if(0 < nxt && nxt <= n){
			if(dp[nxt] > turn+1){
				dp[nxt] = turn+1;
				dfs(nxt, turn+1);
			}
		}
		
	}
}

class Pair{
	int cost;
	int time;
	public Pair(int cost, int time){
		this.cost = cost;
		this.time = time;
	}
}

class MyComp implements Comparator<int[]>{
	public int compare(int[] a, int[] b) {
		return a[0] - b[0];
	}
}

class Reverse implements Comparator<Integer>{
	public int compare(Integer arg0, Integer arg1) {
		return arg1 - arg0;
	}
}

class Node{
	int color;
	boolean checked;
	List<Integer> to = new ArrayList<Integer>();
	public Node(){
		checked = false;
	}
}

//class Node{
//	int id;
//	List<Node> edge = new ArrayList<Node>();
//	public Node(int id){
//		this.id = id;
//	}
//	public void createEdge(Node node){
//		edge.add(node);
//	}
//}

class ContestScanner{
	private BufferedReader reader;
	private String[] line;
	private int idx;
	public ContestScanner() throws FileNotFoundException{
		reader = new BufferedReader(new InputStreamReader(System.in));
	}

	public ContestScanner(String filename) throws FileNotFoundException{
		reader = new BufferedReader(new InputStreamReader(new FileInputStream(filename)));
	}
	
	public String nextToken() throws IOException{
		if(line == null || line.length <= idx){
			line = reader.readLine().trim().split(" ");
			idx = 0;
		}
		return line[idx++];
	}
	public long nextLong() throws IOException, NumberFormatException{
		return Long.parseLong(nextToken());
	}
	public int nextInt() throws NumberFormatException, IOException{
		return (int)nextLong();
	}
	public double nextDouble() throws NumberFormatException, IOException{
		return Double.parseDouble(nextToken());
	}
}