#include<bits/stdc++.h>
using namespace std;

bool dp[10010];

int main(){
    int N;cin>>N;
    int sum = 0;
    vector<int> W(N);
    for(int i=0;i<N;++i) cin>>W[i],sum += W[i];

    dp[0] = true;
  
    for(int i=1;i<=N;++i){
        for(int j=0;j<=sum;++j){
            if(j-W[i-1] < 0) continue;
            if(dp[j-W[i-1]]) dp[j] = true;
        }
    }
    bool ans;
    if(dp[sum/2]) ans = true;
    if(sum%2) ans = false;
    
    cout<<(ans?"possible\n":"impossible\n");
    
}