#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <set>
#include <cmath>
#include <cstring>
#include <iomanip>
#include <random>
#include <chrono>
#include <queue>
using namespace std;
typedef long long ll;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
#define fs first
#define sc second
#define INF 1000000000
#define MOD 1000000007
#define EPS 0.00000001

int main() {
    int N; cin >> N;
    vector<int> W(N);
    int s = 0;
    for(int &w:W){
        cin >> w;
        s += w;
    }
    
    int x = s/2;
    if(x*2!=s){
        cout << "impossible" << endl;
        return 0;
    }
    
    vector<vector<bool>> dp(N+1, vector<bool>(10001));
    dp[0][0] = 1;
    
    for(int i=0; i<N; i++){
        for(int j=0; j<=10000; j++){
            if(j-W[i+1]>=0) dp[i+1][j] = dp[i][j] | dp[i][j-W[i+1]];
            else dp[i+1][j] = dp[i][j];
        }
    }
    
    if(dp[N][x]) cout << "possible" << endl;
    else cout << "impossible" << endl;
    return 0;
}