#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  int W[101];
  int sum = 0;
  bool flag = false;
  cin >> N;
  for(int i = 1;i <= N;i++){
    cin >> W[i];
    sum += W[i];
  }
  if(!(sum & 1)){
    sum /= 2;
    bool dp[101][10001] = {0};
    dp[0][0] = true;
    for(int i = 1;i <= N;i++){
      for(int j = 0;j <= sum;j++){
	dp[i][j] = dp[i - 1][j];
	if(j - W[i] >= 0 && !dp[i][j]){
	  dp[i][j] = dp[i - 1][j - W[i]];
	}
	if(j == sum && dp[i][j] == true){flag = true;break;}
      }
      if(flag)break;
    }
  }
  if(flag)cout << "possible" << endl;
  else cout << "impossible" << endl;
  return 0;
}