#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using Graph=vector<vector<pair<int,int>>>;
using pp=pair<int,pair<int,int>>;
#define MAX 200003
#define MOD 1000000007
#define INF 1000000000

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

  vector<bool> dp(sum+1,false);
  dp.at(0)=true;
  for(int i=0;i<N;i++){
    for(int j=sum;j-W[i]>=0;j--){
      dp[j]=dp[j]|dp[j-W[i]];
    }
  }

  if(sum%2==0){
    if(dp[sum/2]==true){
      cout<<"possible"<<endl;
    }else{
      cout<<"impossible"<<endl;
    }
  }else{
    cout<<"impossible"<<endl;
  }
}