#include<bits/stdc++.h>
using namespace std;
int n,w[100];
int memo[100][10001];
bool solve(int i,int wl,int wr){
  if(wl==wr && i==n){
    return true;
  }
  if(i>n){
    return false;
  }
  if(memo[i][wl]!=-1){
    return memo[i][wl];
  }
  if(solve(i+1,wl+w[i],wr)){
    return true;
  }
  if(solve(i+1,wl,wr+w[i])){
    return true;
  }
  return false;
}

int main(){
  cin>>n;
  for(int i=0;i<n;i++) cin>>w[i];
  memset(memo,-1,sizeof(memo));
  if(solve(0,0,0)==true){
    cout<<"possible"<<endl;
  }else{
    cout<<"impossible"<<endl;
  }
}