#include<iostream>
#include<vector>

using namespace std;

vector<vector<bool>> dp(101,vector<bool>(10001,false));

int main(){
    int n,sum = 0;
    cin >> n;
    int w[n];
    for(int i=0;i < n;i++){
        cin >> w[i];
        sum += w[i];
    }
    if(sum % 2 == 1) {
        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] == true){
                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;
}