#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define rep(i,b) FOR(i,0,b)
#define INF mugen
#define dump(x) cerr<<#x<<"="<<x<<endl
#define all(a) (a).begin(),(a).end()
typedef vector<int> V;
typedef vector<V> VV;
typedef vector<VV> VVV;
template <class T> void chmin(T & a, T const & b) { if (b < a) a = b; }


using ll = long long;
const ll mod = LLONG_MAX;

bool dp[110][10010];
int sum;
int main(){
  int n;
  cin>>n;
  V w(n+1);
  rep(i,n){
    cin>>w[i];
    sum+=w[i];
  }

  if(sum%2!=0){
    cout<<"impossible"<<endl;
    return 0;
  }



  dp[0][0]=1;

  for(int i=1;i<=n;i++){
    rep(j,10010){
      if(j-w[i-1]>=0)dp[i][j]=max(dp[i-1][j],dp[i-1][j-w[i-1]]);
      else dp[i][j]=dp[i-1][j];
    }
  }

  for(int i=1;i<=n;i++){
    if(dp[i][sum/2]){
      cout<<"possible"<<endl;
      return 0;
    }
  }
  cout<<"impossible"<<endl;



}