#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;

bool dp[101][10001]{};
int main(void) {
  cin.tie(0)->sync_with_stdio(false);

  int n;
  cin >> n;
  vector<int> a(n + 1);
  ll sum = 0;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
    sum += a[i];
  }

  for (int i = 1; i <= n; ++i) {
    dp[1][a[i]] = true;
  }
  for (int i = 1; i <= n; ++i) {
    for (int j = 0; j <= sum; ++j) {
      dp[i + 1][j + a[i]] |= dp[i][j];
    }
  }
  if (dp[n / 2][sum / 2]) {
    cout << "possible" << endl;
  } else {
    cout << "impossible" << endl;
  }
  return 0;
}