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

#define rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=int(a);i<int(b);++i)
#define long int64_t
#define ulong uint64_t

const int N = 100;
int n, w[N];

void input()
{
    cin >> n;
    rep(i, n) cin >> w[i];
}

const int W = 10000;
int dp[W + 1] = {1};

bool solve()
{
    const int s = accumulate(w, w + n, 0);
    if (s % 2 != 0) return false;

    rep(i, n) for (int j = W; j >= w[i]; --j) {
        dp[j] |= dp[j - w[i]];
    }
    return dp[s / 2];
}

int main()
{
    cin.tie(0);
    ios_base::sync_with_stdio(false);

    input();
    cout << (solve() ? "possible" : "impossible") << endl;
}