#include<algorithm>
#include<cstdio>
#include<cmath>
#include<iostream>
using namespace std;
int N=0,all=0,w1=0;
int W[110]={0};
int dp[110][10010]={0};
int main(void){
	cin>>N;
	for(int i=0;i<N;i++){
		cin>>W[i];
		all+=W[i];
	}
	w1=all/2;
	if(all%2!=0){}
	else{
		for(int i=0;i<N;i++){
			dp[i+1][W[i]]=1;
			for(int j=1;j<5001;j++){
				if(dp[i][j-W[i]]!=0){
					dp[i+1][j]=1;
				}
			}
		}
	}
	if(dp[N][w1]==1){cout<<"possible"<<endl;}
	else{cout<<"impossible"<<endl;}
	return 0;
}