#include "bits/stdc++.h"
using namespace std;

#define mset(a,x) memset(a,x,sizeof(a))

int N;
vector<int> W;
int sum = 0;

int dp[110][10010];
bool rec(int i, int w) {
    int &r = dp[i][w];
    if (r != -1) return r;
    if (i >= N) return r = (w == sum - w);
    return r = rec(i + 1, w) | rec(i + 1, w + W[i]);
}

int main() {
    cin >> N; W.resize(N);
    for (int& i : W) cin >> i, sum += i;
    mset(dp, -1);
    cout << (rec(0, 0) ? "possible" : "impossible") << endl;
    return 0;
}