#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007;
bool dp[10001];
int main()
{
    int n;
    cin >> n;
    int a[n];
    int sum = 0;
    for (int i = 0; i < n; i++)
    {
        cin >> a[i];
        sum += a[i];
    }
    dp[0] = true;
    for (int i = 0; i < n; i++)
    {
        for (int j = 10000; j >= 0; j--)
        {
            if (dp[j] && dp[i] + j <= 10000)
            {
                dp[j + a[i]] = 1;
            }
        }
    }
    for (int i = 0; i <= 10000; i++)
    {
        if (dp[i])
        {
            if (i * 2 == sum)
            {
                cout << "possible";
                return 0;
            }
        }
    }
    cout << "impossible";
}