#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i))
using ll = long long;
using P = pair<int, int>;
using namespace std;

template<class T> void vin(vector<T>& v, int n) {
    v.resize(n);
    for (int i = 0; i < n; ++i) {
        cin >> v[i];
    }
}

string pos = "possible", imp = "impossible";
int dp[110][10010];
int N, sum;
int W[101];

int solve(int idx, int l) {
    int& res = dp[idx][l];
    if (~res) return res;
    if (sum/2 == l) {
        res = 1;
    }
    else if (idx >= N) {
        res = 0;
    }
    else {
        res = max(solve(idx+1, l), solve(idx+1, l+W[idx]));
    }
    return res;
}

int main() {
    cin >> N;
    rep(i, N) cin >> W[i], sum += W[i];
    if (sum%2) {
        cout << imp << endl;
        return 0;
    }
    fill(dp[0], dp[N], -1);
    cout << (solve(0, 0) == 1 ? pos : imp) << endl;
    return 0;
}