import java.util.*;
import java.util.stream.*;
import static java.lang.Math.*;
public class Main{
	public static void main(String... args){
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		int[] w=new int[n];
		for(int i=0;i<n;i++){
			w[i]=sc.nextInt();
		}
		int wSum=0;
		Set<Integer> set=new HashSet<>();
		set.add(0);
		for(int i=0;i<n;i++){
			wSum+=w[i];
			List<Integer> list=new ArrayList<>(set);
			for(int x:list){
				set.add(x+w[i]);
			}
		}
		if(wSum%2==1){
			put("impossible");
			return;
		}
		if(set.contains(wSum/2)){
			put("possible");
		}else{
			put("impossible");
		}
		
	}
	public static class Pair{
		final int x,y;
		Pair(int x,int y){
			this.x=x;
			this.y=y;
		}
		@Override
		public String toString(){
			return String.format("Pair(%d,%d)",x,y);
		}
	}
	public static void print(Object object){
        System.out.print(object);
    }
    public static void put(Object object) {
        System.out.println(object);
    }
    public static void put(){
        System.out.println();
    }
 
    public static void print(String format,Object... args){
        System.out.print(String.format(format,args));
    }
    public static void put(String format,Object... args) {
        System.out.println(String.format(format,args));
    }
}