#include <bits/stdc++.h>

using namespace std;

template<typename Weight, typename Value> Value knapsack(Weight maxWeight, const vector<Weight>& weight, const vector<Value>& value) {
  vector<Value> dp1(maxWeight + Weight(1)), dp2(maxWeight + Weight(1));
  for (size_t i = 0; i < weight.size(); ++i) {
    for (int w = 0; w <= maxWeight; ++w) {
      Weight ww = Weight(w) + weight[i];
      Value vv = dp1[w] + value[i];
      if (ww <= maxWeight && dp2[ww] < vv) dp2[ww] = vv;
    }
    dp1 = dp2;
  }
  return dp1[maxWeight];
}

template<typename Weight, typename Value = long long> vector<Value> knapsack_counter(Weight maxWeight, const vector<Weight>& weight) {
  vector<Value> dp1(maxWeight + Weight(1)), dp2(maxWeight + Weight(1));
  dp1[0] = dp2[0] = 1;
  for (auto& w : weight) {
    for (int i = 0; i <= maxWeight; ++i) {
      Weight ww = Weight(i) + w;
      if (ww <= maxWeight) dp2[ww] += dp1[i];
    }
    dp1 = dp2;
  }
  return dp1;
}

template<typename Weight> vector<bool> knapsack_fill(Weight maxWeight, const vector<Weight>& weight) {
  vector<bool> dp1(maxWeight + Weight(1)), dp2(maxWeight + Weight(1));
  dp1[0] = dp2[0] = true;
  for (auto& w : weight) {
    for (int i = 0; i <= maxWeight; ++i) {
      Weight ww = Weight(i) + w;
      if (ww <= maxWeight && dp1[i]) dp2[ww] = true;
    }
    dp1 = dp2;
  }
  return dp1;
}

int main() {
  int n;
  cin >> n;
  vector<int> w(n);
  for (int& i : w) cin >> i;
  static const int sum = accumulate(w.begin(), w.end(), 0);
  cout << (sum % 2 == 0 && knapsack_fill(sum / 2, w).back() ? "possible" : "impossible") << endl;
}