#include <iostream>
#include <algorithm>
#include <cstdio>
#include <string>

#define ll long long

using namespace std;

int M[10001];

int main(){

   int n;
   cin>>n;
  
   M[0]=1;
   int W[101],sum=0;
   for(int i=0;i<n;++i){
        cin>>W[i];
        sum+=W[i];
        for(int j=10000-W[i];j>=0;--j)
             if(M[j]) M[j+W[i]]=1;
   }

   if(sum%2||!M[sum/2]){
       cout<<"impossible"<<endl;
       return 0;
   }
   cout<<"possible"<<endl;
   return 0;
}