#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <utility>
#include <stack>
#include <functional>
#include <queue>
#include <cmath>
#include <set>
#include <map>

#define rep(i,j,k) for(int i=(int)j;i<(int)k;i++)
#define Sort(x) sort((x).begin(),(x).end())
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define vi vector<int>
#define INF (int)1e933
#define INFL 1e18
#define MOD 1e9+7
#define pb push_back
#define MP make_pair
typedef long long ll;
typedef std::pair<int,int> pii;
int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};

using namespace std;

int main() {
    int n;cin>>n;
    vector<vector<bool>> dp(n+1,vector<bool>(100*n+1,false));
    dp[0][0]=true;
    int sum=0;
    rep(i,0,n){
        int x;cin>>x;
        sum+=x;
        rep(j,0,100*n+1){
            if(j<x){if(dp[i][j])dp[i+1][j]=true;}
            else if(dp[i][j]||dp[i][j-x])dp[i+1][j]=true;
        }
    }
    if(sum%2==1){
        cout<<"impossible"<<endl;
        return 0;
    }
    if(dp[n][sum/2])cout<<"possible"<<endl;
    else cout<<"impossible"<<endl;
    return 0;
}