#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<int> W(N);
  for (int i = 0; i < N; i++){
    cin >> W[i];
  }
  int sum = 0;
  for (int i = 0; i < N; i++){
    sum += W[i];
  }
  vector<vector<bool>> dp(N + 1, vector<bool>(sum + 1, false));
  dp[0][0] = true;
  for (int i = 0; i < N; i++){
    for (int j = 0; j <= sum; j++){
      if (dp[i][j]){
        dp[i + 1][j] = true;
        dp[i + 1][j + W[i]] = true;
      }
    }
  }
  if (sum % 2 == 0 && dp[N][sum / 2]){
    cout << "possible" << endl;
  } else {
    cout << "impossible" << endl;
  }
}