#include <iostream>
#include <cstring>
using namespace std;
int dp[101][10001] ;
int N,w[100] ,sum = 0 ;
int eql(int i,int j){
     //iは添え字jはi以降の重さの総和
     if(dp[i][j]>=0) return dp[i][j] ;
     int res ;
     if(i==N){
          res = 0 ;
     }else if(j==w[i]){
          res = 1 ;
     }else{
          res = max(eql(i+1,j-w[i]),eql(i+1,j)) ;
     }
     return dp[i][j] = res ;
}


int main(void){
     
     cin >> N ;
     for(int i=0;i<N;i++){
          cin >> w[i] ;
          sum += w[i] ;
     }
     memset(dp,-1,sizeof(dp)) ;
     if(sum%2==0){
          sum /= 2 ;
          if(eql(0,sum)==1) cout << "possible" ;
          else cout << "impossible" ;
     }else{
          cout << "impossible" ;
     }
     
    
}