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

int main()
{
    int n = 0;
    std::cin >> n;

    bool found = false;

    std::vector< int > v;

    for( int i = 0; i < n; ++i )
       {
           int tmp;
           std::cin >> tmp;
           v.push_back(tmp);
       }

    //std::sort(v.begin(), v.end());
    
    std::map<int, bool> dps[201];
    int sum = std::accumulate(v.begin(), v.end(), 0);
    int h = sum/2;
    dps[0][0] = true;
    for(int i = 0; i < n; ++i)
    {
        for(int j = 0; j <= h; ++j)
        {
//            std::cout << "j:" << j << std::endl;
            //驕ｸ縺ｰ縺ｪ縺九▲縺溷�ｴ蜷�
            if(dps[i][j] == true)
            {
                dps[i+1][j] = true;
            }

            //驕ｸ繧薙□蝣ｴ蜷�
            if(j>=v[i]&&dps[i][j - v[i]] == true)
            {
                //std::cout << "!!!" << std::endl;
                dps[i+1][j] = true;
            }
        }
    } 

    for(int i = 0; i < n; ++i)
    {
        for( auto it: dps[i])
        {
  //          std::cout << it.first << ":" << it.second << std::endl;
        }
    }

    if( sum%2==0 && dps[n][h]==true )
        found = true;
    
    if( found )
        std::cout << "possible" << std::endl;
    else
        std::cout << "impossible" << std::endl;

}