#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i,n) for(int i=0; i<(int)n; i++)
#define rep1(i,n) for(int i=1; i<(int)n; i++)
#define repa(i,a,n) for(int i=(a); i<(int)(n); i++)
#define all(vec) vec.begin(),vec.end()
#define COUT(x) cout<<(x)<<endl
#define YES(x) cout<<(x?"YES":"NO")<<endl
#define Yes(x) cout<<(x?"Yes":"No")<<endl
using vi = vector<int>;
using vs = vector<string>;
using vvi = vector<vi>;
using pii = pair<int, int>;
using vpii = vector<pii>;
const int dx[4] = {1, 0,-1, 0};
const int dy[4] = {0, 1, 0,-1};
int gcd(int a, int b){if(a%b == 0){return(b);}else{return(gcd(b, a%b));}}
int lcm(int a, int b){return a/gcd(a, b)*b;}
template <typename T> bool chmax(T &a,const T& b){if(a<b){a=b;return true;}return false;}
template <typename T> bool chmin(T &a,const T& b){if(a>b){a=b;return true;}return false;}
//cout << fixed << setprecision(15);
int N, M, K, H, W, L, R, X, Y;
// string S, T;
const int INF = 1e18;
const int mod = 1e9+7;

signed main(){
    cin >> N;
    int ttlmas = 0;
    vi W(N);
    rep(i,N){
        cin >> W[i];
        ttlmas += W[i]; 
    }
    if(ttlmas%2 != 0){
        COUT("impossible");
        return 0;
    }else ttlmas /= 2;

    set<int> st1;
    set<int> st2;
    rep(i,N){
        st2 = st1;
        for(int a : st2){
            st1.insert(a+W[i]);
        }
        st1.insert(W[i]);
    }
    bool chk = false;
    for(int a : st2){
        if(a == ttlmas){
            chk = true;
            break;
        }
    }
    COUT(chk? "possible":"impossible");
    return 0;
}