#include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <functional>

using namespace std;

#define REP(i,first,last) for (int i=first;i<last;i++)
#define FOR(it,con) for (auto it=con.begin();it!=con.end();it++)

int N;
int half;
vector<int> w_list;
int dp[101][10001] = {};

bool solve(int idx, int total){
  if (dp[idx][total] == 1) {
    return false;
  } else if (dp[idx][total] == 2) {
    return true;
  }
  if (idx >= N || total > half) {
    dp[idx][total] = 1;
    return false;
  }
  int new_total = total + w_list[idx];
  if (new_total == half) {
    dp[idx][total] = 2;
    return true;
  }
  if (solve(idx + 1, new_total) || solve(idx + 1, total)) {
    dp[idx][total] = 2;
    return true;
  }
  dp[idx][total] = 1;
  return false;
}

int main(){
  cin >> N;
  int val;
  int total = 0;
  REP(i,0,N){
    cin >> val;
    w_list.push_back(val);
    total += val;
  }
  sort(w_list.begin(), w_list.end());
  if (total & 1) {
    cout<<"impossible"<<endl;
  } else {
    half = total >> 1;
    if (solve(0, 0)) {
      cout<<"possible"<<endl;
    } else {
      cout<<"impossible"<<endl;
    }
  }
}