#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iostream>
#include <queue>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;

int dp[105][10005];

int main(){
  int N, w;
  vector<int> W;
  cin >> N;
  rep(i,N){
    cin >> w;
    W.push_back(w);
  }

  int sum = 0;
  rep(i,N) sum += W[i];

  dp[0][0] = 1;
  rep(i,N){
    rep(j,10005){
      if(dp[i][j] > 0){
        dp[i+1][j] = 1;
        if(j+W[i]<10005){
          dp[i+1][j+W[i]] = 1;
        }
      }
    }
  }

  rep(i,sum+1){
    if(dp[N][i]==1 && i == sum-i){
      cout << "possible" << endl;
      return 0;
    }
  }
  cout << "impossible" << endl;
  
  return 0;
}