#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int n;
  cin >> n;
  vector<int> w(n);
  rep(i, n) cin >> w[i];
  constexpr int m = 10000;
  vector dp(n + 1, vector<bool>(m + 1, false));
  dp[0][0] = true;
  rep(i, n) {
    rep(j, m) {
      if (dp[i][j]) {
        dp[i + 1][j] = true;
        if (j + w[i] <= m) dp[i + 1][j + w[i]] = true;
      }
    }
  }
  int sum = accumulate(w.begin(), w.end(), 0);
  bool ans = (sum % 2 == 0) && dp[n][sum / 2];
  cout << (ans ? "possible" : "impossible") << endl;
  return 0;
}