#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> P;
 
const int INF = 1e9;
const int mod = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);

int dp[11000] = {1};

int main()
{
    int n;
    cin >> n;
    int sum = 0;
    vector<int> w(n);
    for(int i = 0; i < n; i++){
        cin >> w[i];
        sum += w[i];
    }
    int num = 0;
    for(int i = 0; i < 10010; i++){
        if(dp[i]) dp[i+w[num++]] = 1;
    }
    cout << (sum%2 == 0 && dp[sum/2] ? "possible" : "impossible") << endl;

    return 0;
}