#include<bits/stdc++.h>
using namespace std;
#define all(vec) vec.begin(),vec.end()
typedef long long int ll;
typedef pair<ll,ll> P;
const ll MOD=1000000007;
const ll INF=1000000010;
const ll LINF=4000000000000000010LL;
const int MAX=310;
const double EPS=1e-9;
int dx[4]={0,1,0,1};
int dy[4]={0,0,1,1};
bool dp[110][10010];
int main(){
	int n;cin>>n;
	int w[110];
	int sum=0;
	for(int i=0;i<n;i++){
		cin>>w[i];
		sum+=w[i];
	}
	if(sum%2){
		cout<<"impossible"<<endl;
		return 0;
	}
	dp[0][0]=true;
	for(int i=0;i<n;i++){
		for(int j=0;j<=sum/2;j++){
			dp[i+1][j]|=dp[i][j];
			dp[i+1][j+w[i]]|=dp[i][j];
		}
	}
	if(dp[n][sum/2]){
		cout<<"possible"<<endl;
	}else{
		cout<<"impossible"<<endl;
	}
    return 0;
}