#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<int(n); ++i)
#define repll(i,m,n) for(ll i=m; i<ll(n); ++i)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define fi first
#define se second

template<typename T> bool chmin(T& a, T b){ if(a > b){a = b; return true;} return false; }
template<typename T> bool chmax(T& a, T b){ if(a < b){a = b; return true;} return false; }

template<typename T> T gcd(T a, T b){ return a % b ? gcd(b, a % b) : b; }
template<typename T> T lcm(T a, T b){ return a / gcd(a, b) * b; }

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N;
    cin >> N;
    vector<int> W(N);
    rep(i, 0, N) cin >> W[i];

    int sumW = accumulate(all(W), 0);

    if(sumW & 1){
        cout << "impossible" << endl;
        return 0;
    }

    vector dp(N+1, vector<bool>(sumW + 1, false));
    dp[0][0] = true;

    rep(i, 0, N){
        rep(j, 0, sumW + 1){
            if(!dp[i][j]) continue;
            if(j + W[i] <= sumW) dp[i+1][j + W[i]] = true;
            dp[i+1][j] = true;
        }
    }
    cout << (dp[N][sumW / 2] ? "" : "im") << "possible" << endl;

    return 0;
}