#include <bits/stdc++.h>
// #include <atcoder/all>
// #include "icld.cpp"
using namespace std;
using ll = long long int;
using vi = vector<int>;
using si = set<int>;
using vll = vector<ll>;
using vvi = vector<vector<int>>;
using ss = string;
using db = double;
template<typename T> using minpq = priority_queue <T,vector<T>,greater<T>>;
const int dx[4] = {1,0,-1,0};
const int dy[4] = {0,1,0,-1};
#define V vector
#define P pair<int,int>
#define PLL pair<ll,ll>
#define rep(i,s,n) for(int i=(s);i<(int)(n);i++)
#define rev(i,s,n) for(int i=(s);i>=(int)(n);i--)
#define reciv(v,n) vll (v)((n)); rep(i,0,(n))cin>>v[i]
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define ci(x) cin >> x
#define cii(x) ll x;cin >> x
#define cci(x,y) ll x,y;cin >> x >> y
#define co(x) cout << x << endl
#define pb push_back
#define eb emplace_back
#define rz resize
#define pu push
#define sz(x) int(x.size())
#define vij v[i][j]
// ll p = 1e9+7;
// ll p = 998244353;
// n do -> n*pi/180
#define yn cout<<"Yes"<<endl;else cout<<"No"<<endl
#define YN cout<<"YES"<<endl;else cout<<"NO"<<endl
template<class T>void chmax(T &x,T y){x=max(x,y);}
template<class T>void chmin(T &x,T y){x=min(x,y);}

int main(){
  cii(n);
  reciv(v,n);

  ss ok="possible";
  ss ng="impossible";

  int sum=accumulate(all(v),0);
  if(sum%2)return co(ng),0;
  sum/=2;

  int ma=1e4+3;
  vi dp(ma,0);
  dp[0]=1;

  rep(i,0,n){
    rev(j,ma-1,0){
      if(dp[j])dp[j+v[i]]=1;
    }
  }

  if(dp[sum])co(ok);
  else co(ng);
}