#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define pb push_back
#define mp make_pair
#define rep(i,n) for(int i=0;i<(n);++i)
constexpr int mod=1000000007;
constexpr int mod1=998244353;
vector<int> dx={0,-1,0,1},dy={1,0,-1,0};



int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;cin >> n;
	vector<int> w(n);
	rep(i,n) cin >> w.at(i);
	int sum=0;
	rep(i,n) sum+=w.at(i);
	vector<vector<bool>> dp(n+1,vector<bool>(sum+1));
	dp[0][0]=true;
	rep(i,n){
		rep(j,sum){
			if(dp[i][j]){
				dp[i+1][j]=true;
				dp[i+1][j+w.at(i)]=true;
			}
		}
	}
	bool ans=false;
	rep(i,n+1) if(dp[i][sum/2]) ans=true;
	if(ans && sum%2==0) cout << "possible" << endl;
	else cout << "impossible" << endl;
}