#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <string>
#include <numeric>

#define rep(i, n) for (int i = 0; i < (n); i++)

using ll = long long int;
using namespace std;

int w[100];
bool dp[110][10010] = {false};

int main()
{
    int N, sum = 0;
    cin >> N;
    rep(i, N)
    {
        cin >> w[i];
        sum += w[i];
    }

    if (sum % 2)
    {
        cout << "impossible" << endl;
        return 0;
    }

    dp[0][0] = true;

    for(int i = 0; i < N; i++)
    {
        for(int j = 0; j <= 10000; j++)
        {
            if(dp[i][j])
            {
                dp[i + 1][j + w[i]] = true;
                dp[i + 1][j] = true;
            }
        }
    }

    if(dp[N][sum / 2])
        cout << "possible" << endl;
    else
        cout << "impossible" << endl;

    return 0;
}