#include<bits/stdc++.h>
using namespace std;
#define vi vector<int>
#define pb push_back
#define P pair<int,int>
#define PP pair<P,int>
#define fi first
#define se second
#define INF 1e9
#define MOD 1000000007
#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
bool dp[101][10000];
int main(){
    int n;
    cin>>n;
    vi vec(n);
    int sum=0;
    REP(i,n){
        cin>>vec[i];
        sum+=vec[i];
    }
    if(sum%2){
        cout<<"impossible"<<endl;return 0;
    }
    sum/=2;
    dp[0][0]=true;
    dp[0][vec[0]]=true;
    REP(i,n){
        REP(j,10001){
            if(dp[i][j]){
                dp[i+1][j]=true;
                if(j+vec[i]<=10000){
                    dp[i+1][j+vec[i]]=true;
                }
            }
        }
    }
    if(dp[n][sum]){
        cout<<"possible"<<endl;
    }else{
        cout<<"impossible"<<endl;
    }
    return 0;
}