#include <iostream>
#include <algorithm>
#include <cstring>

using namespace std;

int N, sum = 0;
int w[110];
bool dp[101][10001] = {false};

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

    dp[0][0] = true;

    if (sum % 2 == 1)
    {
        cout << "impossible" << endl;
        return 0;
    }

    int m = sum / 2;
    for(int i = 0; i < N; i++)
    {
       for(int j = 0; j <= 100000; j++)
       {
           if(dp[i][j])
           {
               dp[i + 1][j + w[i]] = true;
               dp[i + 1][j] = true;
           }
       }
    }

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