#include<iostream>
using namespace std;
int main(){
    int n,w,sum=0;
    bool able[101][101]={};
    cin >> n;
    able[0][0]=true;
    for(int i=1;i<=n;i++){
        cin >> w;
        sum+=w;
        for(int j=0;j<=100;j++){
            able[i][j]=able[i-1][j];
            if(j>=w&&able[i-1][j-w]) able[i][j]=true;
        }
    }
    if(sum%2==0&&able[n][sum/2])cout <<"possible\n";
    else cout << "impossible\n";
}