#include <iostream>
#include <cstring>
using namespace std;
int dp[101][5001] ;
int main(void){
     int N , w[100],sum = 0 ;
     cin >> N ;
     for(int i=0;i<N;i++){
          cin >> w[i] ;
          sum += w[i] ;
     }
     
     if(sum%2==0){
          sum /= 2 ;
          for(int i=N-1;i>=0;i--){
               for(int j=0;j<=sum;j++){
                    if(j==w[i]){
                         dp[i][j] = 1 ;
                    }else{
                         dp[i][j] = max(dp[i+1][j-w[i]],dp[i+1][j]) ;
                    }
               }
          }
          if(dp[0][sum]==1) cout << "possible" ;
          else cout << "impossible" ; 
     }else{
          cout << "impossible" ;
     }
     
    
}