#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ul;
typedef signed long long ll;
ul over = 1000000007;

int main(void)
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed;
  ll n;
  cin >> n;
  ll w[n];
  ll w_sum = 0;
  for (ll i = 0; i < n; ++i) {
    cin >> w[i];
    w_sum += w[i];
  }
  if (w_sum%2==1) {cout << "impossible" << endl; return 0;}
  bool dp[n][w_sum/2+1];
  for (ll i = 0; i < n; ++i) {
    for (ll j = 0; j <= w_sum/2; ++j) dp[i][j] = false;
  }
  dp[0][0] = true;
  if (w[0] <= w_sum/2) dp[0][w[0]] = true;
  for (ll i = 1; i < n; ++i) {
    for (ll wi = 0; wi <= w_sum/2; ++wi) {
      if (dp[i-1][wi]) {
        dp[i][wi] = true;
        if (wi + w[i] <= w_sum/2) dp[i][wi+w[i]] = true;
      }
    }
  }
  cout << (dp[n-1][w_sum/2] ? "possible" : "impossible") << endl;
  return 0;
}