#include<bits/stdc++.h>
using namespace std;
#define inf 1000000000
#define INF 1000000000000000
#define ll long long
#define ull unsigned long long
#define M (int)(1e9+7)
#define P pair<int,int>
#define PLL pair<ll,ll>
#define FOR(i,m,n) for(int i=(int)m;i<(int)n;i++)
#define RFOR(i,m,n) for(int i=(int)m;i>=(int)n;i--)
#define rep(i,n) FOR(i,0,n)
#define rrep(i,n) RFOR(i,n,0)
#define all(a) a.begin(),a.end()
#define IN(a,n) rep(i,n){ cin>>a[i]; }
const int vx[4] = {0,1,0,-1};
const int vy[4] = {1,0,-1,0};
#define PI 3.14159265
#define F first
#define S second
#define PB push_back
#define EB emplace_back
#define int ll
void init(){
  cin.tie(0);
  ios::sync_with_stdio(false);
}


bool dp[110000][110];

main(){
  int n;
  int sum=0;
  cin>>n;
  vector<int> v(n+1);
  rep(i,n){
    cin>>v[i+1];
    sum+=v[i+1];
  }

  dp[0][0]=true;

  FOR(i,1,n+1){
    rep(j,sum+1){
      dp[i][j]|=dp[i-1][j];
      dp[i][j+v[i]]|=dp[i-1][j];
    }
  }

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

}