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

int N;
int S;
int dp[2][10001];

int main() {
    cin >> N;
    S = 0;
    rep(i, 10001) dp[0][i] = 0; dp[0][0] = 1;
    rep(i, N) {
        int w; cin >> w;
        S += w;
        rep(j, 10001) dp[1][j] = dp[0][j];
        rep(j, 10001) if (w <= j) dp[0][j] |= dp[1][j - w];
    }

    bool ok = false;
    if (S % 2 == 0) if (dp[0][S / 2]) ok = true;
    cout << (ok ? "possible" : "impossible") << endl;

    return 0;
}