#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
ll INF = 1e18;

int main(){
    int N;
    cin >> N;
    int w[N+1];
    ll tot = 0;
    rep(i,1,N+1) {
        cin >> w[i];
        tot += w[i];
    }

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

    if(tot%2==0 && dp[N][tot/2]) {
        cout << "possible" << endl;
    }
    else cout << "impossible" << endl;
    return 0;
}