#include <iostream>
using namespace std;
typedef long long ll;

int main(void)
{
    int N;
    cin >> N;
    ll sum=0;
    int dp[11000] = {0};
    dp[0] = 1;
    for(int i=0; i<N; i++)
    {
        int a;
        cin >> a;
        sum += a;
        for(int j=0; j<11000; j++)
            if(dp[j] && j+a<11000) dp[j+a] = 1;
    }

    if(!(sum&1) && dp[sum/2])
        cout << "possible" << endl;
    else
        cout << "impossible" << endl;

    return 0;
}