#include <bits/stdc++.h>
//#define int long long

using namespace std;
using LL = long long;
using P = pair<int, int>;
using Tapris = tuple<int, int, int>;

#define FOR(i, a, n) for(int i = (int)(a); i < (int)(n); ++i)
#define REP(i, n) FOR(i, 0, n)

#define pb(a) push_back(a)
#define all(x) (x).begin(),(x).end()

const int INF = (int)1e9;
const LL INFL = (LL)1e15;
const int MOD = 1e9 + 7;

int dy[]={0, 0, 1, -1, 0};
int dx[]={1, -1, 0, 0, 0};

/*************** using variables ***************/
int n;
int w[105];
int dp[105][10005];
/**********************************************/

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    cin >> n;
    REP(i, n) cin >> w[i];
    
    REP(i, 105) REP(j, 10005) dp[i][j] = -1;
    dp[0][0] = 0;
    REP(i, n){
        REP(j, 10001){
            if(dp[i][j] != -1){
                dp[i+1][j] = dp[i][j] + w[i];
                dp[i+1][j+w[i]] = dp[i][j];
            }
        }
    }

    bool flag = false;
    REP(j, 10001){
        if(dp[n][j] == j) flag = true;
    }
    if(flag) cout << "possible" << endl;
    else cout << "impossible" << endl;

}