#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

bool solve(const vector<int>& w)
{
    int n = w.size();
    int sum = accumulate(w.begin(), w.end(), 0);
    if(sum % 2 != 0)
        return false;

    int half = sum / 2;
    vector<bool> dp(half + 1, false);
    dp[0] = true;
    for(int i=0; i<n; ++i){
        for(int j=half-w[i]; j>=0; --j){
            if(dp[j])
                dp[j+w[i]] = true;
        }
    }
    return dp[half];
}

int main()
{
    int n;
    cin >> n;
    vector<int> w(n);
    for(int i=0; i<n; ++i)
        cin >> w[i];

    if(solve(w))
        cout << "possible" << endl;
    else
        cout << "impossible" << endl;

    return 0;
}