#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define chmin(x,y) x = min((x),(y));
#define chmax(x,y) x = max((x),(y));
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
const int INF = 1e9;
const long long LINF = 1e17;
const int MOD = 1000000007;
//const int MOD = 998244353;
const double PI = 3.14159265358979323846;

int main(){
    int n;
    cin >> n;
    vector<int> w(n);
    rep(i,n) cin >> w[i];
    bitset<100005> dp;
    dp[0] = 1;
    int W = 0;
    rep(i,n) W += w[i];
    rep(i,n){
        dp = (dp|dp<<w[i]);
    }
    if(W%2==1) cout << "impossible" << endl;
    else{
        if(dp[W/2]) cout << "possible" << endl;
        else cout << "impossible" << endl;
    }
    return 0;
}